40402639 has 4 divisors (see below), whose sum is σ = 40626040. Its totient is φ = 40179240.

The previous prime is 40402633. The next prime is 40402643. The reversal of 40402639 is 93620404.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 40402639 - 2⁹ = 40402127 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (40402633) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 111429 + ... + 111790.

It is an arithmetic number, because the mean of its divisors is an integer number (10156510).

Almost surely, 2^40402639 is an apocalyptic number.

40402639 is a deficient number, since it is larger than the sum of its proper divisors (223401).

40402639 is a wasteful number, since it uses less digits than its factorization.

40402639 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 223400.

The product of its (nonzero) digits is 5184, while the sum is 28.

The square root of 40402639 is about 6356.3070253096. The cubic root of 40402639 is about 343.1388654797.

It can be divided in two parts, 40402 and 639, that added together give a triangular number (41041 = T₂₈₆).

The spelling of 40402639 in words is "forty million, four hundred two thousand, six hundred thirty-nine".