40257639 has 18 divisors (see below), whose sum is σ = 59204808. Its totient is φ = 26355000.

The previous prime is 40257631. The next prime is 40257641. The reversal of 40257639 is 93675204.

It is not a de Polignac number, because 40257639 - 2³ = 40257631 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (40257631) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 160264 + ... + 160514.

It is an arithmetic number, because the mean of its divisors is an integer number (3289156).

Almost surely, 2^40257639 is an apocalyptic number.

40257639 is a deficient number, since it is larger than the sum of its proper divisors (18947169).

40257639 is an equidigital number, since it uses as much as digits as its factorization.

40257639 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 579 (or 325 counting only the distinct ones).

The product of its (nonzero) digits is 45360, while the sum is 36.

The square root of 40257639 is about 6344.8907792018. The cubic root of 40257639 is about 342.7278793220.

It can be divided in two parts, 4025 and 7639, that added together give a square (11664 = 108²).

The spelling of 40257639 in words is "forty million, two hundred fifty-seven thousand, six hundred thirty-nine".