21959427 has 16 divisors (see below), whose sum is σ = 35430912. Its totient is φ = 11809920.

The previous prime is 21959423. The next prime is 21959449. The reversal of 21959427 is 72495912.

It is not a de Polignac number, because 21959427 - 2² = 21959423 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21959423) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 30399 + ... + 31112.

It is an arithmetic number, because the mean of its divisors is an integer number (2214432).

Almost surely, 2^21959427 is an apocalyptic number.

21959427 is a deficient number, since it is larger than the sum of its proper divisors (13471485).

21959427 is a wasteful number, since it uses less digits than its factorization.

21959427 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 61538.

The product of its digits is 45360, while the sum is 39.

The square root of 21959427 is about 4686.0886675350. The cubic root of 21959427 is about 280.0315738204.

The spelling of 21959427 in words is "twenty-one million, nine hundred fifty-nine thousand, four hundred twenty-seven".