1981163520 has 576 divisors, whose sum is σ = 8156453760. Its totient is φ = 435290112.

The previous prime is 1981163519. The next prime is 1981163533. The reversal of 1981163520 is 253611891.

1981163520 is a `hidden beast` number, since 1 + 9 + 8 + 11 + 635 + 2 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (576).

It is a super-3 number, since 3×1981163520³ (a number of 29 digits) contains 333 as substring.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 23869399 + ... + 23869481.

It is an arithmetic number, because the mean of its divisors is an integer number (14160510).

Almost surely, 2^1981163520 is an apocalyptic number.

1981163520 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 1981163520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (4078226880).

1981163520 is an abundant number, since it is smaller than the sum of its proper divisors (6175290240).

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

1981163520 is a wasteful number, since it uses less digits than its factorization.

1981163520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 160 (or 137 counting only the distinct ones).

The product of its (nonzero) digits is 12960, while the sum is 36.

The square root of 1981163520 is about 44510.2630861692. The cubic root of 1981163520 is about 1255.9531538913.

The spelling of 1981163520 in words is "one billion, nine hundred eighty-one million, one hundred sixty-three thousand, five hundred twenty".