21121456 has 10 divisors (see below), whose sum is σ = 40922852. Its totient is φ = 10560720.

The previous prime is 21121453. The next prime is 21121493. The reversal of 21121456 is 65412112.

It is a super-2 number, since 2×21121456² = 892231807119872, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21121453) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 660030 + ... + 660061.

Almost surely, 2^21121456 is an apocalyptic number.

It is an amenable number.

21121456 is a deficient number, since it is larger than the sum of its proper divisors (19801396).

21121456 is a wasteful number, since it uses less digits than its factorization.

21121456 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1320099 (or 1320093 counting only the distinct ones).

The product of its digits is 480, while the sum is 22.

The square root of 21121456 is about 4595.8085251673. The cubic root of 21121456 is about 276.4232810597.

Adding to 21121456 its reverse (65412112), we get a palindrome (86533568).

The spelling of 21121456 in words is "twenty-one million, one hundred twenty-one thousand, four hundred fifty-six".