21557153 has 4 divisors (see below), whose sum is σ = 22691760. Its totient is φ = 20422548.

The previous prime is 21557143. The next prime is 21557177. The reversal of 21557153 is 35175512.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21557153 - 2¹² = 21553057 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21557113) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 567275 + ... + 567312.

It is an arithmetic number, because the mean of its divisors is an integer number (5672940).

Almost surely, 2^21557153 is an apocalyptic number.

It is an amenable number.

21557153 is a deficient number, since it is larger than the sum of its proper divisors (1134607).

21557153 is a wasteful number, since it uses less digits than its factorization.

21557153 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1134606.

The product of its digits is 5250, while the sum is 29.

The square root of 21557153 is about 4642.9681239483. The cubic root of 21557153 is about 278.3110616798.

The spelling of 21557153 in words is "twenty-one million, five hundred fifty-seven thousand, one hundred fifty-three".