21749901815041 has 9 divisors (see below), whose sum is σ = 21786783915459. Its totient is φ = 21713082069336.

The previous prime is 21749901815027. The next prime is 21749901815053. The reversal of 21749901815041 is 14051810994712.

The square root of 21749901815041 is 4663679.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 15867356058225 + 5882545756816 = 3983385^2 + 2425396^2 .

It is not a de Polignac number, because 21749901815041 - 2²³ = 21749893426433 is a prime.

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 21749901815041.

It is not an unprimeable number, because it can be changed into a prime (21749901015041) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 2998741971 + ... + 2998749223.

Almost surely, 2^{21749901815041} is an apocalyptic number.

21749901815041 is the 4663679-th square number.

21749901815041 is the 2331840-th centered octagonal number.

It is an amenable number.

21749901815041 is a deficient number, since it is larger than the sum of its proper divisors (36882100418).

21749901815041 is an frugal number, since it uses more digits than its factorization.

21749901815041 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15792 (or 7896 counting only the distinct ones).

The product of its (nonzero) digits is 725760, while the sum is 52.

The spelling of 21749901815041 in words is "twenty-one trillion, seven hundred forty-nine billion, nine hundred one million, eight hundred fifteen thousand, forty-one".