21487245 has 32 divisors (see below), whose sum is σ = 37425024. Its totient is φ = 10464000.

The previous prime is 21487243. The next prime is 21487261. The reversal of 21487245 is 54278412.

It is not a de Polignac number, because 21487245 - 2¹ = 21487243 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21487243) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 19150 + ... + 20240.

It is an arithmetic number, because the mean of its divisors is an integer number (1169532).

Almost surely, 2^21487245 is an apocalyptic number.

It is an amenable number.

21487245 is a deficient number, since it is larger than the sum of its proper divisors (15937779).

21487245 is a wasteful number, since it uses less digits than its factorization.

21487245 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1213.

The product of its digits is 17920, while the sum is 33.

The square root of 21487245 is about 4635.4336366731. The cubic root of 21487245 is about 278.0098895780.

The spelling of 21487245 in words is "twenty-one million, four hundred eighty-seven thousand, two hundred forty-five".