16157978 has 4 divisors (see below), whose sum is σ = 24236970. Its totient is φ = 8078988.

The previous prime is 16157971. The next prime is 16157993. The reversal of 16157978 is 87975161.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 8334769 + 7823209 = 2887^2 + 2797^2 .

It is a super-2 number, since 2×16157978² = 522160506096968, which contains 22 as substring.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (16157971) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4039493 + ... + 4039496.

Almost surely, 2^16157978 is an apocalyptic number.

16157978 is a deficient number, since it is larger than the sum of its proper divisors (8078992).

16157978 is an equidigital number, since it uses as much as digits as its factorization.

16157978 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8078991.

The product of its digits is 105840, while the sum is 44.

The square root of 16157978 is about 4019.6987449310. The cubic root of 16157978 is about 252.8108278790.

The spelling of 16157978 in words is "sixteen million, one hundred fifty-seven thousand, nine hundred seventy-eight".