21797853 has 32 divisors (see below), whose sum is σ = 36495360. Its totient is φ = 11242560.

The previous prime is 21797843. The next prime is 21797857. The reversal of 21797853 is 35879712.

It is not a de Polignac number, because 21797853 - 2⁸ = 21797597 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21797857) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 45268 + ... + 45746.

It is an arithmetic number, because the mean of its divisors is an integer number (1140480).

Almost surely, 2^21797853 is an apocalyptic number.

It is an amenable number.

21797853 is a deficient number, since it is larger than the sum of its proper divisors (14697507).

21797853 is a wasteful number, since it uses less digits than its factorization.

21797853 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 697.

The product of its digits is 105840, while the sum is 42.

The square root of 21797853 is about 4668.8170878714. The cubic root of 21797853 is about 279.3430730398.

The spelling of 21797853 in words is "twenty-one million, seven hundred ninety-seven thousand, eight hundred fifty-three".