917121664 has 32 divisors (see below), whose sum is σ = 1876468500. Its totient is φ = 446164992.

The previous prime is 917121649. The next prime is 917121677. The reversal of 917121664 is 466121719.

It can be written as a sum of positive squares in 2 ways, for example, as 621006400 + 296115264 = 24920^2 + 17208^2 .

It is a tau number, because it is divible by the number of its divisors (32).

It is a super-2 number, since 2×917121664² = 1682224293156257792, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (37).

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, 92089 + ... + 101560.

Almost surely, 2^917121664 is an apocalyptic number.

It is an amenable number.

917121664 is an abundant number, since it is smaller than the sum of its proper divisors (959346836).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

917121664 is a wasteful number, since it uses less digits than its factorization.

917121664 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 193700 (or 193688 counting only the distinct ones).

The product of its digits is 18144, while the sum is 37.

The square root of 917121664 is about 30284.0166424469. The cubic root of 917121664 is about 971.5734776750.

The spelling of 917121664 in words is "nine hundred seventeen million, one hundred twenty-one thousand, six hundred sixty-four".