161021520 has 280 divisors, whose sum is σ = 614773152. Its totient is φ = 38880000.

The previous prime is 161021519. The next prime is 161021591. The reversal of 161021520 is 25120161.

161021520 is a `hidden beast` number, since 1 + 610 + 2 + 1 + 52 + 0 = 666.

161021520 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a super-2 number, since 2×161021520² = 51855859806220800, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a junction number, because it is equal to n+sod(n) for n = 161021493 and 161021502.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 55 ways as a sum of consecutive naturals, for example, 641395 + ... + 641645.

Almost surely, 2^161021520 is an apocalyptic number.

161021520 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 161021520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (307386576).

161021520 is an abundant number, since it is smaller than the sum of its proper divisors (453751632).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

161021520 is a wasteful number, since it uses less digits than its factorization.

161021520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 293 (or 272 counting only the distinct ones).

The product of its (nonzero) digits is 120, while the sum is 18.

The square root of 161021520 is about 12689.4255189114. The cubic root of 161021520 is about 544.0364198512.

Adding to 161021520 its reverse (25120161), we get a palindrome (186141681).

The spelling of 161021520 in words is "one hundred sixty-one million, twenty-one thousand, five hundred twenty".