21653156 has 24 divisors (see below), whose sum is σ = 43505280. Its totient is φ = 9237312.

The previous prime is 21653153. The next prime is 21653167. The reversal of 21653156 is 65135612.

It is not an unprimeable number, because it can be changed into a prime (21653153) 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 7 ways as a sum of consecutive naturals, for example, 4865 + ... + 8183.

It is an arithmetic number, because the mean of its divisors is an integer number (1812720).

Almost surely, 2^21653156 is an apocalyptic number.

It is an amenable number.

21653156 is an abundant number, since it is smaller than the sum of its proper divisors (21852124).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21653156 is a wasteful number, since it uses less digits than its factorization.

21653156 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3563 (or 3561 counting only the distinct ones).

The product of its digits is 5400, while the sum is 29.

The square root of 21653156 is about 4653.2951765389. The cubic root of 21653156 is about 278.7235949973.

Adding to 21653156 its reverse (65135612), we get a palindrome (86788768).

The spelling of 21653156 in words is "twenty-one million, six hundred fifty-three thousand, one hundred fifty-six".