161503904 has 12 divisors (see below), whose sum is σ = 317960874. Its totient is φ = 80751936.

The previous prime is 161503877. The next prime is 161503919. The reversal of 161503904 is 409305161.

It can be written as a sum of positive squares in only one way, i.e., 155052304 + 6451600 = 12452^2 + 2540^2 .

It is a super-2 number, since 2×161503904² = 52167022014482432, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2523467 + ... + 2523530.

Almost surely, 2^161503904 is an apocalyptic number.

It is an amenable number.

161503904 is a deficient number, since it is larger than the sum of its proper divisors (156456970).

161503904 is an equidigital number, since it uses as much as digits as its factorization.

161503904 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5047007 (or 5046999 counting only the distinct ones).

The product of its (nonzero) digits is 3240, while the sum is 29.

The square root of 161503904 is about 12708.4186270362. The cubic root of 161503904 is about 544.5791482081.

The spelling of 161503904 in words is "one hundred sixty-one million, five hundred three thousand, nine hundred four".