21764394453 has 4 divisors (see below), whose sum is σ = 29019192608. Its totient is φ = 14509596300.

The previous prime is 21764394439. The next prime is 21764394473. The reversal of 21764394453 is 35449346712.

It is a happy number.

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 not a de Polignac number, because 21764394453 - 2¹² = 21764390357 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 (21764394473) 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, 3627399073 + ... + 3627399078.

It is an arithmetic number, because the mean of its divisors is an integer number (7254798152).

Almost surely, 2^21764394453 is an apocalyptic number.

It is an amenable number.

21764394453 is a deficient number, since it is larger than the sum of its proper divisors (7254798155).

21764394453 is an equidigital number, since it uses as much as digits as its factorization.

21764394453 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7254798154.

The product of its digits is 2177280, while the sum is 48.

The spelling of 21764394453 in words is "twenty-one billion, seven hundred sixty-four million, three hundred ninety-four thousand, four hundred fifty-three".