21542159 has 2 divisors, whose sum is σ = 21542160. Its totient is φ = 21542158.

The previous prime is 21542153. The next prime is 21542161. The reversal of 21542159 is 95124512.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21542159 is a prime.

It is a super-2 number, since 2×21542159² = 928129228762562, which contains 22 as substring.

Together with 21542161, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21542153) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10771079 + 10771080.

It is an arithmetic number, because the mean of its divisors is an integer number (10771080).

Almost surely, 2^21542159 is an apocalyptic number.

21542159 is a deficient number, since it is larger than the sum of its proper divisors (1).

21542159 is an equidigital number, since it uses as much as digits as its factorization.

21542159 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3600, while the sum is 29.

The square root of 21542159 is about 4641.3531432116. The cubic root of 21542159 is about 278.2465206288.

The spelling of 21542159 in words is "twenty-one million, five hundred forty-two thousand, one hundred fifty-nine".