21440751 has 8 divisors (see below), whose sum is σ = 28629120. Its totient is φ = 14273112.

The previous prime is 21440719. The next prime is 21440801. The reversal of 21440751 is 15704412.

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

It is not a de Polignac number, because 21440751 - 2⁵ = 21440719 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21440051) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2581 + ... + 7038.

It is an arithmetic number, because the mean of its divisors is an integer number (3578640).

Almost surely, 2^21440751 is an apocalyptic number.

21440751 is a deficient number, since it is larger than the sum of its proper divisors (7188369).

21440751 is an equidigital number, since it uses as much as digits as its factorization.

21440751 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10365.

The product of its (nonzero) digits is 1120, while the sum is 24.

The square root of 21440751 is about 4630.4158560544. The cubic root of 21440751 is about 277.8092259447.

It can be divided in two parts, 2 and 1440751, that added together give a triangular number (1440753 = T₁₆₉₇).

The spelling of 21440751 in words is "twenty-one million, four hundred forty thousand, seven hundred fifty-one".