21097236 has 24 divisors (see below), whose sum is σ = 50815744. Its totient is φ = 6805440.

The previous prime is 21097231. The next prime is 21097261. The reversal of 21097236 is 63279012.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21097231) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 27985 + ... + 28728.

Almost surely, 2^21097236 is an apocalyptic number.

It is an amenable number.

21097236 is an abundant number, since it is smaller than the sum of its proper divisors (29718508).

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

21097236 is a wasteful number, since it uses less digits than its factorization.

21097236 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 56751 (or 56749 counting only the distinct ones).

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

The square root of 21097236 is about 4593.1727596510. The cubic root of 21097236 is about 276.3175823404.

The spelling of 21097236 in words is "twenty-one million, ninety-seven thousand, two hundred thirty-six".