161213955840 has 432 divisors, whose sum is σ = 638624645568. Its totient is φ = 36782014464.

The previous prime is 161213955839. The next prime is 161213955857. The reversal of 161213955840 is 48559312161.

It is a happy number.

161213955840 is a `hidden beast` number, since 1 + 6 + 1 + 21 + 39 + 558 + 40 = 666.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

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, 54591804 + ... + 54594756.

Almost surely, 2^161213955840 is an apocalyptic number.

161213955840 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 161213955840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (319312322784).

161213955840 is an abundant number, since it is smaller than the sum of its proper divisors (477410689728).

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

161213955840 is a wasteful number, since it uses less digits than its factorization.

161213955840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3664 (or 3647 counting only the distinct ones).

The product of its (nonzero) digits is 259200, while the sum is 45.

The spelling of 161213955840 in words is "one hundred sixty-one billion, two hundred thirteen million, nine hundred fifty-five thousand, eight hundred forty".