21753949 has 8 divisors (see below), whose sum is σ = 25283520. Its totient is φ = 18329856.

The previous prime is 21753937. The next prime is 21753961. The reversal of 21753949 is 94935712.

It is an interprime number because it is at equal distance from previous prime (21753937) and next prime (21753961).

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 21753949 - 2¹⁹ = 21229661 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 (21753989) 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, 25924 + ... + 26749.

It is an arithmetic number, because the mean of its divisors is an integer number (3160440).

Almost surely, 2^21753949 is an apocalyptic number.

It is an amenable number.

21753949 is a deficient number, since it is larger than the sum of its proper divisors (3529571).

21753949 is an equidigital number, since it uses as much as digits as its factorization.

21753949 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 52739.

The product of its digits is 68040, while the sum is 40.

The square root of 21753949 is about 4664.1128845687. The cubic root of 21753949 is about 279.1554013226.

The spelling of 21753949 in words is "twenty-one million, seven hundred fifty-three thousand, nine hundred forty-nine".