21639702 has 16 divisors (see below), whose sum is σ = 49462272. Its totient is φ = 6182760.

The previous prime is 21639701. The next prime is 21639703. The reversal of 21639702 is 20793612.

It is an interprime number because it is at equal distance from previous prime (21639701) and next prime (21639703).

It is a self number, because there is not a number n which added to its sum of digits gives 21639702.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21639701) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 257574 + ... + 257657.

It is an arithmetic number, because the mean of its divisors is an integer number (3091392).

Almost surely, 2^21639702 is an apocalyptic number.

21639702 is an abundant number, since it is smaller than the sum of its proper divisors (27822570).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21639702 is a wasteful number, since it uses less digits than its factorization.

21639702 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 515243.

The product of its (nonzero) digits is 4536, while the sum is 30.

The square root of 21639702 is about 4651.8493096832. The cubic root of 21639702 is about 278.6658555438.

The spelling of 21639702 in words is "twenty-one million, six hundred thirty-nine thousand, seven hundred two".