21677139 has 20 divisors (see below), whose sum is σ = 35327160. Its totient is φ = 13137120.

The previous prime is 21677137. The next prime is 21677141. The reversal of 21677139 is 93177612.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (21677137) and next prime (21677141).

It is not a de Polignac number, because 21677139 - 2¹ = 21677137 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21677137) 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 19 ways as a sum of consecutive naturals, for example, 11274 + ... + 13055.

It is an arithmetic number, because the mean of its divisors is an integer number (1766358).

Almost surely, 2^21677139 is an apocalyptic number.

21677139 is a deficient number, since it is larger than the sum of its proper divisors (13650021).

21677139 is a wasteful number, since it uses less digits than its factorization.

21677139 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24352 (or 24343 counting only the distinct ones).

The product of its digits is 15876, while the sum is 36.

The square root of 21677139 is about 4655.8714544111. The cubic root of 21677139 is about 278.8264616269.

It can be divided in two parts, 21677 and 139, that multiplied together give a palindrome (3013103).

The spelling of 21677139 in words is "twenty-one million, six hundred seventy-seven thousand, one hundred thirty-nine".