64397778 has 16 divisors (see below), whose sum is σ = 128874240. Its totient is φ = 21452816.

The previous prime is 64397771. The next prime is 64397803. The reversal of 64397778 is 87779346.

It is a super-2 number, since 2×64397778² = 8294147622674568, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 64397778.

It is not an unprimeable number, because it can be changed into a prime (64397771) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 17308 + ... + 20696.

It is an arithmetic number, because the mean of its divisors is an integer number (8054640).

Almost surely, 2^64397778 is an apocalyptic number.

64397778 is an abundant number, since it is smaller than the sum of its proper divisors (64476462).

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

64397778 is a wasteful number, since it uses less digits than its factorization.

64397778 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6561.

The product of its digits is 1778112, while the sum is 51.

The square root of 64397778 is about 8024.8226148620. The cubic root of 64397778 is about 400.8269931940.

The spelling of 64397778 in words is "sixty-four million, three hundred ninety-seven thousand, seven hundred seventy-eight".