21661059 has 8 divisors (see below), whose sum is σ = 33007360. Its totient is φ = 12377736.

The previous prime is 21661051. The next prime is 21661061. The reversal of 21661059 is 95016612.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21661059 - 2³ = 21661051 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21661051) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 515719 + ... + 515760.

It is an arithmetic number, because the mean of its divisors is an integer number (4125920).

Almost surely, 2^21661059 is an apocalyptic number.

21661059 is a deficient number, since it is larger than the sum of its proper divisors (11346301).

21661059 is a wasteful number, since it uses less digits than its factorization.

21661059 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1031489.

The product of its (nonzero) digits is 3240, while the sum is 30.

The square root of 21661059 is about 4654.1442822500. The cubic root of 21661059 is about 278.7575005187.

The spelling of 21661059 in words is "twenty-one million, six hundred sixty-one thousand, fifty-nine".