21242415256 has 32 divisors (see below), whose sum is σ = 41826025440. Its totient is φ = 10094692608.

The previous prime is 21242415239. The next prime is 21242415277. The reversal of 21242415256 is 65251424212.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 338781 + ... + 396556.

It is an arithmetic number, because the mean of its divisors is an integer number (1307063295).

Almost surely, 2^21242415256 is an apocalyptic number.

It is an amenable number.

21242415256 is a deficient number, since it is larger than the sum of its proper divisors (20583610184).

21242415256 is a wasteful number, since it uses less digits than its factorization.

21242415256 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 735523 (or 735519 counting only the distinct ones).

The product of its digits is 38400, while the sum is 34.

Adding to 21242415256 its reverse (65251424212), we get a palindrome (86493839468).

The spelling of 21242415256 in words is "twenty-one billion, two hundred forty-two million, four hundred fifteen thousand, two hundred fifty-six".