161994651 has 16 divisors (see below), whose sum is σ = 265837824. Its totient is φ = 85447584.

The previous prime is 161994629. The next prime is 161994689. The reversal of 161994651 is 156499161.

It is not a de Polignac number, because 161994651 - 2⁵ = 161994619 is a prime.

It is a super-2 number, since 2×161994651² = 52484533905223602, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (161994611) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 296421 + ... + 296966.

It is an arithmetic number, because the mean of its divisors is an integer number (16614864).

Almost surely, 2^161994651 is an apocalyptic number.

161994651 is a deficient number, since it is larger than the sum of its proper divisors (103843173).

161994651 is a wasteful number, since it uses less digits than its factorization.

161994651 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 593410.

The product of its digits is 58320, while the sum is 42.

The square root of 161994651 is about 12727.7119310582. The cubic root of 161994651 is about 545.1301779206.

The spelling of 161994651 in words is "one hundred sixty-one million, nine hundred ninety-four thousand, six hundred fifty-one".