21551159 has 4 divisors (see below), whose sum is σ = 24629904. Its totient is φ = 18472416.

The previous prime is 21551143. The next prime is 21551171. The reversal of 21551159 is 95115512.

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

It is a cyclic number.

It is not a de Polignac number, because 21551159 - 2⁴ = 21551143 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21551119) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1539362 + ... + 1539375.

It is an arithmetic number, because the mean of its divisors is an integer number (6157476).

Almost surely, 2^21551159 is an apocalyptic number.

21551159 is a deficient number, since it is larger than the sum of its proper divisors (3078745).

21551159 is an equidigital number, since it uses as much as digits as its factorization.

21551159 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3078744.

The product of its digits is 2250, while the sum is 29.

The square root of 21551159 is about 4642.3225868093. The cubic root of 21551159 is about 278.2852643471.

The spelling of 21551159 in words is "twenty-one million, five hundred fifty-one thousand, one hundred fifty-nine".