21764951 has 8 divisors (see below), whose sum is σ = 23539824. Its totient is φ = 20004480.

The previous prime is 21764933. The next prime is 21764959. The reversal of 21764951 is 15946712.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21764951 - 2⁶ = 21764887 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21764959) 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 7 ways as a sum of consecutive naturals, for example, 341 + ... + 6606.

It is an arithmetic number, because the mean of its divisors is an integer number (2942478).

Almost surely, 2^21764951 is an apocalyptic number.

21764951 is a deficient number, since it is larger than the sum of its proper divisors (1774873).

21764951 is a wasteful number, since it uses less digits than its factorization.

21764951 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7201.

The product of its digits is 15120, while the sum is 35.

The square root of 21764951 is about 4665.2921666279. The cubic root of 21764951 is about 279.2024540839.

The spelling of 21764951 in words is "twenty-one million, seven hundred sixty-four thousand, nine hundred fifty-one".