21859396 has 24 divisors (see below), whose sum is σ = 42205464. Its totient is φ = 9841920.

The previous prime is 21859393. The next prime is 21859403. The reversal of 21859396 is 69395812.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 1932100 + 19927296 = 1390^2 + 4464^2 .

It is not an unprimeable number, because it can be changed into a prime (21859391) 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, 2995 + ... + 7258.

It is an arithmetic number, because the mean of its divisors is an integer number (1758561).

Almost surely, 2^21859396 is an apocalyptic number.

21859396 is a gapful number since it is divisible by the number (26) formed by its first and last digit.

It is an amenable number.

21859396 is a deficient number, since it is larger than the sum of its proper divisors (20346068).

21859396 is a wasteful number, since it uses less digits than its factorization.

21859396 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10311 (or 10309 counting only the distinct ones).

The product of its digits is 116640, while the sum is 43.

The square root of 21859396 is about 4675.4032981124. The cubic root of 21859396 is about 279.6057205698.

The spelling of 21859396 in words is "twenty-one million, eight hundred fifty-nine thousand, three hundred ninety-six".