161212945640 has 32 divisors (see below), whose sum is σ = 362767437000. Its totient is φ = 64478367744.

The previous prime is 161212945637. The next prime is 161212945651. The reversal of 161212945640 is 46549212161.

It can be written as a sum of positive squares in 4 ways, for example, as 128770451716 + 32442493924 = 358846^2 + 180118^2 .

It is a super-2 number, since 2×161212945640² (a number of 23 digits) contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 179576 + ... + 595544.

Almost surely, 2^161212945640 is an apocalyptic number.

161212945640 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

161212945640 is an abundant number, since it is smaller than the sum of its proper divisors (201554491360).

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

161212945640 is a wasteful number, since it uses less digits than its factorization.

161212945640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 425669 (or 425665 counting only the distinct ones).

The product of its (nonzero) digits is 103680, while the sum is 41.

The spelling of 161212945640 in words is "one hundred sixty-one billion, two hundred twelve million, nine hundred forty-five thousand, six hundred forty".