21561134 has 36 divisors (see below), whose sum is σ = 39809304. Its totient is φ = 8577792.

The previous prime is 21561131. The next prime is 21561167. The reversal of 21561134 is 43116512.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21561131) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 295322 + ... + 295394.

It is an arithmetic number, because the mean of its divisors is an integer number (1105814).

Almost surely, 2^21561134 is an apocalyptic number.

21561134 is a deficient number, since it is larger than the sum of its proper divisors (18248170).

21561134 is an equidigital number, since it uses as much as digits as its factorization.

21561134 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 189 (or 99 counting only the distinct ones).

The product of its digits is 720, while the sum is 23.

The square root of 21561134 is about 4643.3968169865. The cubic root of 21561134 is about 278.3281927011.

Adding to 21561134 its reverse (43116512), we get a palindrome (64677646).

The spelling of 21561134 in words is "twenty-one million, five hundred sixty-one thousand, one hundred thirty-four".