21209196 has 24 divisors (see below), whose sum is σ = 49929264. Its totient is φ = 7006720.

The previous prime is 21209189. The next prime is 21209207. The reversal of 21209196 is 69190212.

It is a happy number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6465 + ... + 9176.

It is an arithmetic number, because the mean of its divisors is an integer number (2080386).

Almost surely, 2^21209196 is an apocalyptic number.

It is an amenable number.

21209196 is an abundant number, since it is smaller than the sum of its proper divisors (28720068).

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

21209196 is a wasteful number, since it uses less digits than its factorization.

21209196 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15761 (or 15759 counting only the distinct ones).

The product of its (nonzero) digits is 1944, while the sum is 30.

The square root of 21209196 is about 4605.3442868042. The cubic root of 21209196 is about 276.8055127985.

The spelling of 21209196 in words is "twenty-one million, two hundred nine thousand, one hundred ninety-six".