15777961 has 4 divisors (see below), whose sum is σ = 16608400. Its totient is φ = 14947524.

The previous prime is 15777953. The next prime is 15777991. The reversal of 15777961 is 16977751.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 15777961 - 2³ = 15777953 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (15777901) 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, 415191 + ... + 415228.

It is an arithmetic number, because the mean of its divisors is an integer number (4152100).

Almost surely, 2^15777961 is an apocalyptic number.

It is an amenable number.

15777961 is a deficient number, since it is larger than the sum of its proper divisors (830439).

15777961 is an equidigital number, since it uses as much as digits as its factorization.

15777961 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 830438.

The product of its digits is 92610, while the sum is 43.

The square root of 15777961 is about 3972.1481593717. The cubic root of 15777961 is about 250.8131443178.

The spelling of 15777961 in words is "fifteen million, seven hundred seventy-seven thousand, nine hundred sixty-one".