21610139 has 4 divisors (see below), whose sum is σ = 21619680. Its totient is φ = 21600600.

The previous prime is 21610103. The next prime is 21610151. The reversal of 21610139 is 93101612.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21610139 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21610439) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 782 + ... + 6620.

It is an arithmetic number, because the mean of its divisors is an integer number (5404920).

Almost surely, 2^21610139 is an apocalyptic number.

21610139 is a deficient number, since it is larger than the sum of its proper divisors (9541).

21610139 is an equidigital number, since it uses as much as digits as its factorization.

21610139 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9540.

The product of its (nonzero) digits is 324, while the sum is 23.

The square root of 21610139 is about 4648.6706702024. The cubic root of 21610139 is about 278.5388982646.

The spelling of 21610139 in words is "twenty-one million, six hundred ten thousand, one hundred thirty-nine".