15977 has 4 divisors (see below), whose sum is σ = 17220. Its totient is φ = 14736.

The previous prime is 15973. The next prime is 15991. The reversal of 15977 is 77951.

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

It can be written as a sum of positive squares in 2 ways, for example, as 10201 + 5776 = 101^2 + 76^2 .

It is a cyclic number.

It is not a de Polignac number, because 15977 - 2² = 15973 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (15971) 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, 602 + ... + 627.

It is an arithmetic number, because the mean of its divisors is an integer number (4305).

2¹⁵⁹⁷⁷ is an apocalyptic number.

It is an amenable number.

15977 is a deficient number, since it is larger than the sum of its proper divisors (1243).

15977 is a wasteful number, since it uses less digits than its factorization.

15977 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1242.

The product of its digits is 2205, while the sum is 29.

The square root of 15977 is about 126.4001582277. The cubic root of 15977 is about 25.1863409643.

The spelling of 15977 in words is "fifteen thousand, nine hundred seventy-seven".