161651522563440 has 960 divisors, whose sum is σ = 661035141043200. Its totient is φ = 32300950929408.

The previous prime is 161651522563429. The next prime is 161651522563457. The reversal of 161651522563440 is 44365225156161.

It is a super-2 number, since 2×161651522563440² (a number of 29 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 191 ways as a sum of consecutive naturals, for example, 11133784501 + ... + 11133799019.

It is an arithmetic number, because the mean of its divisors is an integer number (688578271920).

Almost surely, 2^{161651522563440} is an apocalyptic number.

161651522563440 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 161651522563440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (330517570521600).

161651522563440 is an abundant number, since it is smaller than the sum of its proper divisors (499383618479760).

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

161651522563440 is a wasteful number, since it uses less digits than its factorization.

161651522563440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18414 (or 18401 counting only the distinct ones).

The product of its (nonzero) digits is 5184000, while the sum is 51.

The spelling of 161651522563440 in words is "one hundred sixty-one trillion, six hundred fifty-one billion, five hundred twenty-two million, five hundred sixty-three thousand, four hundred forty".