21868042 has 16 divisors (see below), whose sum is σ = 37630080. Its totient is φ = 9336528.

The previous prime is 21868039. The next prime is 21868043. The reversal of 21868042 is 24086812.

It is a super-2 number, since 2×21868042² = 956422521827528, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21867995 and 21868013.

It is not an unprimeable number, because it can be changed into a prime (21868043) 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, 1059 + ... + 6697.

It is an arithmetic number, because the mean of its divisors is an integer number (2351880).

Almost surely, 2^21868042 is an apocalyptic number.

21868042 is a deficient number, since it is larger than the sum of its proper divisors (15762038).

21868042 is a wasteful number, since it uses less digits than its factorization.

21868042 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5925.

The product of its (nonzero) digits is 6144, while the sum is 31.

The square root of 21868042 is about 4676.3278328193. The cubic root of 21868042 is about 279.6425796609.

The spelling of 21868042 in words is "twenty-one million, eight hundred sixty-eight thousand, forty-two".