64821638 has 16 divisors (see below), whose sum is σ = 111227904. Its totient is φ = 27754440.

The previous prime is 64821623. The next prime is 64821643. The reversal of 64821638 is 83612846.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 23723 + ... + 26313.

It is an arithmetic number, because the mean of its divisors is an integer number (6951744).

Almost surely, 2^64821638 is an apocalyptic number.

64821638 is a deficient number, since it is larger than the sum of its proper divisors (46406266).

64821638 is a wasteful number, since it uses less digits than its factorization.

64821638 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4387.

The product of its digits is 55296, while the sum is 38.

The square root of 64821638 is about 8051.1886079013. The cubic root of 64821638 is about 401.7044724511.

The spelling of 64821638 in words is "sixty-four million, eight hundred twenty-one thousand, six hundred thirty-eight".