21879242 has 32 divisors (see below), whose sum is σ = 42246144. Its totient is φ = 8247600.

The previous prime is 21879239. The next prime is 21879269. The reversal of 21879242 is 24297812.

It is a Smith number, since the sum of its digits (35) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2483 + ... + 7065.

It is an arithmetic number, because the mean of its divisors is an integer number (1320192).

Almost surely, 2^21879242 is an apocalyptic number.

21879242 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

21879242 is a deficient number, since it is larger than the sum of its proper divisors (20366902).

21879242 is a wasteful number, since it uses less digits than its factorization.

21879242 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4634.

The product of its digits is 16128, while the sum is 35.

The square root of 21879242 is about 4677.5252003597. The cubic root of 21879242 is about 279.6903123652.

The spelling of 21879242 in words is "twenty-one million, eight hundred seventy-nine thousand, two hundred forty-two".