161902978 has 8 divisors (see below), whose sum is σ = 242910972. Its totient is φ = 80932656.

The previous prime is 161902943. The next prime is 161902981. The reversal of 161902978 is 879209161.

It can be written as a sum of positive squares in 2 ways, for example, as 153933649 + 7969329 = 12407^2 + 2823^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 7176 + ... + 19372.

Almost surely, 2^161902978 is an apocalyptic number.

161902978 is a deficient number, since it is larger than the sum of its proper divisors (81007994).

161902978 is a wasteful number, since it uses less digits than its factorization.

161902978 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18836.

The product of its (nonzero) digits is 54432, while the sum is 43.

The square root of 161902978 is about 12724.1101064082. The cubic root of 161902978 is about 545.0273285401.

The spelling of 161902978 in words is "one hundred sixty-one million, nine hundred two thousand, nine hundred seventy-eight".