161901616 has 20 divisors (see below), whose sum is σ = 314323632. Its totient is φ = 80785856.

The previous prime is 161901583. The next prime is 161901617. The reversal of 161901616 is 616109161.

It is a happy number.

It is a super-2 number, since 2×161901616² = 52424266526822912, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (161901617) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2011 + ... + 18106.

Almost surely, 2^161901616 is an apocalyptic number.

161901616 is a gapful number since it is divisible by the number (16) formed by its first and last digit.

It is an amenable number.

161901616 is a deficient number, since it is larger than the sum of its proper divisors (152422016).

161901616 is a wasteful number, since it uses less digits than its factorization.

161901616 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20628 (or 20622 counting only the distinct ones).

The product of its (nonzero) digits is 1944, while the sum is 31.

The square root of 161901616 is about 12724.0565858534. The cubic root of 161901616 is about 545.0258001982.

The spelling of 161901616 in words is "one hundred sixty-one million, nine hundred one thousand, six hundred sixteen".