161394371690 has 64 divisors (see below), whose sum is σ = 316703284128. Its totient is φ = 58976870400.

The previous prime is 161394371689. The next prime is 161394371771. The reversal of 161394371690 is 96173493161.

It is a happy number.

It can be written as a sum of positive squares in 16 ways, for example, as 9288911641 + 152105460049 = 96379^2 + 390007^2 .

It is a super-2 number, since 2×161394371690² (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 31 ways as a sum of consecutive naturals, for example, 1314320 + ... + 1431860.

Almost surely, 2^161394371690 is an apocalyptic number.

161394371690 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

161394371690 is a deficient number, since it is larger than the sum of its proper divisors (155308912438).

161394371690 is a wasteful number, since it uses less digits than its factorization.

161394371690 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 117803.

The product of its (nonzero) digits is 734832, while the sum is 50.

The spelling of 161394371690 in words is "one hundred sixty-one billion, three hundred ninety-four million, three hundred seventy-one thousand, six hundred ninety".