21764741 has 4 divisors (see below), whose sum is σ = 21821952. Its totient is φ = 21707532.

The previous prime is 21764723. The next prime is 21764773. The reversal of 21764741 is 14746712.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21764741 - 2²² = 17570437 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21764698 and 21764707.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21764711) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 28031 + ... + 28796.

It is an arithmetic number, because the mean of its divisors is an integer number (5455488).

Almost surely, 2^21764741 is an apocalyptic number.

It is an amenable number.

21764741 is a deficient number, since it is larger than the sum of its proper divisors (57211).

21764741 is an equidigital number, since it uses as much as digits as its factorization.

21764741 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 57210.

The product of its digits is 9408, while the sum is 32.

The square root of 21764741 is about 4665.2696599446. The cubic root of 21764741 is about 279.2015561157.

The spelling of 21764741 in words is "twenty-one million, seven hundred sixty-four thousand, seven hundred forty-one".