161621115290 has 16 divisors (see below), whose sum is σ = 293041499112. Its totient is φ = 64176559104.

The previous prime is 161621115197. The next prime is 161621115301. The reversal of 161621115290 is 92511126161.

It can be written as a sum of positive squares in 4 ways, for example, as 149918419249 + 11702696041 = 387193^2 + 108179^2 .

It is a super-2 number, since 2×161621115290² (a number of 23 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 161621115290.

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 7 ways as a sum of consecutive naturals, for example, 58984439 + ... + 58987178.

Almost surely, 2^161621115290 is an apocalyptic number.

161621115290 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

161621115290 is a deficient number, since it is larger than the sum of its proper divisors (131420383822).

161621115290 is a wasteful number, since it uses less digits than its factorization.

161621115290 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 117971761.

The product of its (nonzero) digits is 6480, while the sum is 35.

The spelling of 161621115290 in words is "one hundred sixty-one billion, six hundred twenty-one million, one hundred fifteen thousand, two hundred ninety".