65640638 has 32 divisors (see below), whose sum is σ = 119620800. Its totient is φ = 26371584.

The previous prime is 65640629. The next prime is 65640647. The reversal of 65640638 is 83604656.

It is an interprime number because it is at equal distance from previous prime (65640629) and next prime (65640647).

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, 92228 + ... + 92936.

It is an arithmetic number, because the mean of its divisors is an integer number (3738150).

Almost surely, 2^65640638 is an apocalyptic number.

65640638 is a deficient number, since it is larger than the sum of its proper divisors (53980162).

65640638 is a wasteful number, since it uses less digits than its factorization.

65640638 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1124.

The product of its (nonzero) digits is 103680, while the sum is 38.

The square root of 65640638 is about 8101.8910138313. The cubic root of 65640638 is about 403.3891980691.

The spelling of 65640638 in words is "sixty-five million, six hundred forty thousand, six hundred thirty-eight".