21767139 has 12 divisors (see below), whose sum is σ = 32526000. Its totient is φ = 14010864.

The previous prime is 21767099. The next prime is 21767147. The reversal of 21767139 is 93176712.

It is a happy number.

It is not a de Polignac number, because 21767139 - 2²¹ = 19669987 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21767149) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 41439 + ... + 41960.

It is an arithmetic number, because the mean of its divisors is an integer number (2710500).

Almost surely, 2^21767139 is an apocalyptic number.

21767139 is a gapful number since it is divisible by the number (29) formed by its first and last digit.

21767139 is a deficient number, since it is larger than the sum of its proper divisors (10758861).

21767139 is a wasteful number, since it uses less digits than its factorization.

21767139 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 83434 (or 83431 counting only the distinct ones).

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

The square root of 21767139 is about 4665.5266583742. The cubic root of 21767139 is about 279.2118097141.

The spelling of 21767139 in words is "twenty-one million, seven hundred sixty-seven thousand, one hundred thirty-nine".