161211112520 has 64 divisors (see below), whose sum is σ = 383959224000. Its totient is φ = 60812898048.

The previous prime is 161211112519. The next prime is 161211112567. The reversal of 161211112520 is 25211112161.

It is a happy number.

It is a super-2 number, since 2×161211112520² (a number of 23 digits) contains 22 as substring.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1566110 + ... + 1665869.

It is an arithmetic number, because the mean of its divisors is an integer number (5999362875).

Almost surely, 2^161211112520 is an apocalyptic number.

161211112520 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

161211112520 is an abundant number, since it is smaller than the sum of its proper divisors (222748111480).

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

161211112520 is a wasteful number, since it uses less digits than its factorization.

161211112520 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3232062 (or 3232058 counting only the distinct ones).

The product of its (nonzero) digits is 240, while the sum is 23.

Adding to 161211112520 its reverse (25211112161), we get a palindrome (186422224681).

The spelling of 161211112520 in words is "one hundred sixty-one billion, two hundred eleven million, one hundred twelve thousand, five hundred twenty".