21542859 has 24 divisors (see below), whose sum is σ = 35485632. Its totient is φ = 12476160.

The previous prime is 21542849. The next prime is 21542879. The reversal of 21542859 is 95824512.

It is not a de Polignac number, because 21542859 - 2¹⁷ = 21411787 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21542849) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 3427 + ... + 7404.

It is an arithmetic number, because the mean of its divisors is an integer number (1478568).

Almost surely, 2^21542859 is an apocalyptic number.

21542859 is a deficient number, since it is larger than the sum of its proper divisors (13942773).

21542859 is a wasteful number, since it uses less digits than its factorization.

21542859 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10867 (or 10864 counting only the distinct ones).

The product of its digits is 28800, while the sum is 36.

The square root of 21542859 is about 4641.4285516423. The cubic root of 21542859 is about 278.2495344160.

The spelling of 21542859 in words is "twenty-one million, five hundred forty-two thousand, eight hundred fifty-nine".