21415245 has 32 divisors (see below), whose sum is σ = 35223552. Its totient is φ = 11107392.

The previous prime is 21415217. The next prime is 21415249. The reversal of 21415245 is 54251412.

It is not a de Polignac number, because 21415245 - 2⁵ = 21415213 is a prime.

It is a super-2 number, since 2×21415245² = 917225436820050, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21415249) 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, 128152 + ... + 128318.

It is an arithmetic number, because the mean of its divisors is an integer number (1100736).

Almost surely, 2^21415245 is an apocalyptic number.

It is an amenable number.

21415245 is a deficient number, since it is larger than the sum of its proper divisors (13808307).

21415245 is a wasteful number, since it uses less digits than its factorization.

21415245 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 361.

The product of its digits is 1600, while the sum is 24.

The square root of 21415245 is about 4627.6608561994. The cubic root of 21415245 is about 277.6990212580.

Adding to 21415245 its reverse (54251412), we get a palindrome (75666657).

The spelling of 21415245 in words is "twenty-one million, four hundred fifteen thousand, two hundred forty-five".