21510472 has 16 divisors (see below), whose sum is σ = 40885740. Its totient is φ = 10607616.

The previous prime is 21510469. The next prime is 21510479. The reversal of 21510472 is 27401512.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 19589476 + 1920996 = 4426^2 + 1386^2 .

It is not an unprimeable number, because it can be changed into a prime (21510479) 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, 17833 + ... + 19000.

Almost surely, 2^21510472 is an apocalyptic number.

It is an amenable number.

21510472 is a deficient number, since it is larger than the sum of its proper divisors (19375268).

21510472 is a wasteful number, since it uses less digits than its factorization.

21510472 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 36912 (or 36908 counting only the distinct ones).

The product of its (nonzero) digits is 560, while the sum is 22.

The square root of 21510472 is about 4637.9383350795. The cubic root of 21510472 is about 278.1100266652.

Adding to 21510472 its reverse (27401512), we get a palindrome (48911984).

The spelling of 21510472 in words is "twenty-one million, five hundred ten thousand, four hundred seventy-two".