74021639 has 4 divisors (see below), whose sum is σ = 74042640. Its totient is φ = 74000640.

The previous prime is 74021617. The next prime is 74021653. The reversal of 74021639 is 93612047.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-74021639 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 (74021669) 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, 3779 + ... + 12740.

It is an arithmetic number, because the mean of its divisors is an integer number (18510660).

Almost surely, 2^74021639 is an apocalyptic number.

74021639 is a deficient number, since it is larger than the sum of its proper divisors (21001).

74021639 is a wasteful number, since it uses less digits than its factorization.

74021639 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21000.

The product of its (nonzero) digits is 9072, while the sum is 32.

The square root of 74021639 is about 8603.5829164366. The cubic root of 74021639 is about 419.8745638262.

The spelling of 74021639 in words is "seventy-four million, twenty-one thousand, six hundred thirty-nine".