21121874 has 4 divisors (see below), whose sum is σ = 31682814. Its totient is φ = 10560936.

The previous prime is 21121853. The next prime is 21121883. The reversal of 21121874 is 47812112.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 20638849 + 483025 = 4543^2 + 695^2 .

It is a super-2 number, since 2×21121874² = 892267122543752, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5280467 + ... + 5280470.

Almost surely, 2^21121874 is an apocalyptic number.

21121874 is a deficient number, since it is larger than the sum of its proper divisors (10560940).

21121874 is a wasteful number, since it uses less digits than its factorization.

21121874 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10560939.

The product of its digits is 896, while the sum is 26.

The square root of 21121874 is about 4595.8540011624. The cubic root of 21121874 is about 276.4251045477.

Adding to 21121874 its reverse (47812112), we get a palindrome (68933986).

The spelling of 21121874 in words is "twenty-one million, one hundred twenty-one thousand, eight hundred seventy-four".