21676951 has 4 divisors (see below), whose sum is σ = 21753832. Its totient is φ = 21600072.

The previous prime is 21676943. The next prime is 21676957. The reversal of 21676951 is 15967612.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21676951 - 2³ = 21676943 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21676951.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21676957) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 38016 + ... + 38581.

It is an arithmetic number, because the mean of its divisors is an integer number (5438458).

Almost surely, 2^21676951 is an apocalyptic number.

21676951 is a deficient number, since it is larger than the sum of its proper divisors (76881).

21676951 is an equidigital number, since it uses as much as digits as its factorization.

21676951 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 76880.

The product of its digits is 22680, while the sum is 37.

The square root of 21676951 is about 4655.8512648065. The cubic root of 21676951 is about 278.8256555622.

The spelling of 21676951 in words is "twenty-one million, six hundred seventy-six thousand, nine hundred fifty-one".