947664921 has 32 divisors (see below), whose sum is σ = 1464530688. Its totient is φ = 533894400.

The previous prime is 947664911. The next prime is 947664931. The reversal of 947664921 is 129466749.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (947664911) and next prime (947664931).

It is not a de Polignac number, because 947664921 - 2⁷ = 947664793 is a prime.

It is not an unprimeable number, because it can be changed into a prime (947664911) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 586711 + ... + 588323.

It is an arithmetic number, because the mean of its divisors is an integer number (45766584).

Almost surely, 2^947664921 is an apocalyptic number.

It is an amenable number.

947664921 is a deficient number, since it is larger than the sum of its proper divisors (516865767).

947664921 is a wasteful number, since it uses less digits than its factorization.

947664921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2001.

The product of its digits is 653184, while the sum is 48.

The square root of 947664921 is about 30784.1667257699. The cubic root of 947664921 is about 982.2414752731.

The spelling of 947664921 in words is "nine hundred forty-seven million, six hundred sixty-four thousand, nine hundred twenty-one".