664155870 has 32 divisors (see below), whose sum is σ = 1821685248. Its totient is φ = 151807008.

The previous prime is 664155859. The next prime is 664155917. The reversal of 664155870 is 78551466.

It is a super-2 number, since 2×664155870² = 882206039310913800, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1581114 + ... + 1581533.

It is an arithmetic number, because the mean of its divisors is an integer number (56927664).

Almost surely, 2^664155870 is an apocalyptic number.

664155870 is an abundant number, since it is smaller than the sum of its proper divisors (1157529378).

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

664155870 is a wasteful number, since it uses less digits than its factorization.

664155870 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3162664.

The product of its (nonzero) digits is 201600, while the sum is 42.

The square root of 664155870 is about 25771.2217405384. The cubic root of 664155870 is about 872.4823936043.

The spelling of 664155870 in words is "six hundred sixty-four million, one hundred fifty-five thousand, eight hundred seventy".