21431137 has 32 divisors (see below), whose sum is σ = 27869184. Its totient is φ = 16027200.

The previous prime is 21431131. The next prime is 21431141. The reversal of 21431137 is 73113412.

It is not a de Polignac number, because 21431137 - 2³ = 21431129 is a prime.

It is a super-2 number, since 2×21431137² = 918587266225538, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21431131) 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, 200238 + ... + 200344.

It is an arithmetic number, because the mean of its divisors is an integer number (870912).

Almost surely, 2^21431137 is an apocalyptic number.

It is an amenable number.

21431137 is a deficient number, since it is larger than the sum of its proper divisors (6438047).

21431137 is a wasteful number, since it uses less digits than its factorization.

21431137 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 229.

The product of its digits is 504, while the sum is 22.

The square root of 21431137 is about 4629.3776039550. The cubic root of 21431137 is about 277.7676966593.

Adding to 21431137 its reverse (73113412), we get a palindrome (94544549).

The spelling of 21431137 in words is "twenty-one million, four hundred thirty-one thousand, one hundred thirty-seven".