21618476 has 12 divisors (see below), whose sum is σ = 41271720. Its totient is φ = 9826560.

The previous prime is 21618451. The next prime is 21618479. The reversal of 21618476 is 67481612.

It is not an unprimeable number, because it can be changed into a prime (21618479) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 245621 + ... + 245708.

It is an arithmetic number, because the mean of its divisors is an integer number (3439310).

Almost surely, 2^21618476 is an apocalyptic number.

It is an amenable number.

21618476 is a deficient number, since it is larger than the sum of its proper divisors (19653244).

21618476 is a wasteful number, since it uses less digits than its factorization.

21618476 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 491344 (or 491342 counting only the distinct ones).

The product of its digits is 16128, while the sum is 35.

The square root of 21618476 is about 4649.5672916950. The cubic root of 21618476 is about 278.5747129383.

The spelling of 21618476 in words is "twenty-one million, six hundred eighteen thousand, four hundred seventy-six".