21744495651 has 4 divisors (see below), whose sum is σ = 28992660872. Its totient is φ = 14496330432.

The previous prime is 21744495623. The next prime is 21744495653. The reversal of 21744495651 is 15659444712.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 21744495651 - 2⁶ = 21744495587 is a prime.

It is a super-2 number, since 2×21744495651² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21744495651.

It is not an unprimeable number, because it can be changed into a prime (21744495653) 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, 3624082606 + ... + 3624082611.

It is an arithmetic number, because the mean of its divisors is an integer number (7248165218).

Almost surely, 2^21744495651 is an apocalyptic number.

21744495651 is a deficient number, since it is larger than the sum of its proper divisors (7248165221).

21744495651 is an equidigital number, since it uses as much as digits as its factorization.

21744495651 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7248165220.

The product of its digits is 1209600, while the sum is 48.

The spelling of 21744495651 in words is "twenty-one billion, seven hundred forty-four million, four hundred ninety-five thousand, six hundred fifty-one".