21996039 has 12 divisors (see below), whose sum is σ = 31626168. Its totient is φ = 13518000.

The previous prime is 21996001. The next prime is 21996041. The reversal of 21996039 is 93069912.

It is a happy number.

It is not a de Polignac number, because 21996039 - 2⁹ = 21995527 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (39).

It is a junction number, because it is equal to n+sod(n) for n = 21995988 and 21996006.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21996089) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 28914 + ... + 29664.

It is an arithmetic number, because the mean of its divisors is an integer number (2635514).

Almost surely, 2^21996039 is an apocalyptic number.

21996039 is a deficient number, since it is larger than the sum of its proper divisors (9630129).

21996039 is an frugal number, since it uses more digits than its factorization.

21996039 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1518 (or 767 counting only the distinct ones).

The product of its (nonzero) digits is 26244, while the sum is 39.

The square root of 21996039 is about 4689.9934967972. The cubic root of 21996039 is about 280.1871155747.

Multiplying 21996039 by its sum of digits (39), we get a square (857845521 = 29289²).

21996039 divided by its sum of digits (39) gives a square (564001 = 751²).

The spelling of 21996039 in words is "twenty-one million, nine hundred ninety-six thousand, thirty-nine".