21644759364452 has 36 divisors (see below), whose sum is σ = 44167707223920. Its totient is φ = 9254186205264.

The previous prime is 21644759364433. The next prime is 21644759364457. The reversal of 21644759364452 is 25446395744612.

It is a super-2 number, since 2×21644759364452² (a number of 27 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21644759364457) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 131698838 + ... + 131863085.

It is an arithmetic number, because the mean of its divisors is an integer number (1226880756220).

Almost surely, 2^{21644759364452} is an apocalyptic number.

It is an amenable number.

21644759364452 is an abundant number, since it is smaller than the sum of its proper divisors (22522947859468).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21644759364452 is a wasteful number, since it uses less digits than its factorization.

21644759364452 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 263562360 (or 263562351 counting only the distinct ones).

The product of its digits is 174182400, while the sum is 62.

The spelling of 21644759364452 in words is "twenty-one trillion, six hundred forty-four billion, seven hundred fifty-nine million, three hundred sixty-four thousand, four hundred fifty-two".