21551474 has 24 divisors (see below), whose sum is σ = 38413440. Its totient is φ = 9037896.

The previous prime is 21551459. The next prime is 21551503. The reversal of 21551474 is 47415512.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2267 + ... + 6945.

It is an arithmetic number, because the mean of its divisors is an integer number (1600560).

Almost surely, 2^21551474 is an apocalyptic number.

21551474 is a deficient number, since it is larger than the sum of its proper divisors (16861966).

21551474 is a wasteful number, since it uses less digits than its factorization.

21551474 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4742 (or 4735 counting only the distinct ones).

The product of its digits is 5600, while the sum is 29.

The square root of 21551474 is about 4642.3565136685. The cubic root of 21551474 is about 278.2866201819.

Adding to 21551474 its reverse (47415512), we get a palindrome (68966986).

The spelling of 21551474 in words is "twenty-one million, five hundred fifty-one thousand, four hundred seventy-four".