21224497 has 8 divisors (see below), whose sum is σ = 24752000. Its totient is φ = 18192132.

The previous prime is 21224479. The next prime is 21224503. The reversal of 21224497 is 79442212.

It is a de Polignac number, because none of the positive numbers 2^k-21224497 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21224447) 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, 30597 + ... + 31282.

It is an arithmetic number, because the mean of its divisors is an integer number (3094000).

Almost surely, 2^21224497 is an apocalyptic number.

It is an amenable number.

21224497 is a deficient number, since it is larger than the sum of its proper divisors (3527503).

21224497 is an frugal number, since it uses more digits than its factorization.

21224497 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 61900 (or 61886 counting only the distinct ones).

The product of its digits is 8064, while the sum is 31.

The square root of 21224497 is about 4607.0052094609. The cubic root of 21224497 is about 276.8720622808.

The spelling of 21224497 in words is "twenty-one million, two hundred twenty-four thousand, four hundred ninety-seven".