21634131 has 4 divisors (see below), whose sum is σ = 28845512. Its totient is φ = 14422752.

The previous prime is 21634127. The next prime is 21634133. The reversal of 21634131 is 13143612.

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

It is not a de Polignac number, because 21634131 - 2² = 21634127 is a prime.

It is a super-2 number, since 2×21634131² = 936071248250322, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21634098 and 21634107.

It is not an unprimeable number, because it can be changed into a prime (21634133) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3605686 + ... + 3605691.

It is an arithmetic number, because the mean of its divisors is an integer number (7211378).

Almost surely, 2^21634131 is an apocalyptic number.

21634131 is a deficient number, since it is larger than the sum of its proper divisors (7211381).

21634131 is an equidigital number, since it uses as much as digits as its factorization.

21634131 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7211380.

The product of its digits is 432, while the sum is 21.

The square root of 21634131 is about 4651.2504770223. The cubic root of 21634131 is about 278.6419399230.

Adding to 21634131 its reverse (13143612), we get a palindrome (34777743).

The spelling of 21634131 in words is "twenty-one million, six hundred thirty-four thousand, one hundred thirty-one".