21266751 has 8 divisors (see below), whose sum is σ = 30933504. Its totient is φ = 12888920.

The previous prime is 21266737. The next prime is 21266753. The reversal of 21266751 is 15766212.

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

It is not a de Polignac number, because 21266751 - 2⁹ = 21266239 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21266753) 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 7 ways as a sum of consecutive naturals, for example, 322191 + ... + 322256.

It is an arithmetic number, because the mean of its divisors is an integer number (3866688).

Almost surely, 2^21266751 is an apocalyptic number.

21266751 is a deficient number, since it is larger than the sum of its proper divisors (9666753).

21266751 is a wasteful number, since it uses less digits than its factorization.

21266751 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 644461.

The product of its digits is 5040, while the sum is 30.

The square root of 21266751 is about 4611.5887717792. The cubic root of 21266751 is about 277.0556739697.

The spelling of 21266751 in words is "twenty-one million, two hundred sixty-six thousand, seven hundred fifty-one".