21759850718545 has 8 divisors (see below), whose sum is σ = 26111993529960. Its totient is φ = 17407765463040.

The previous prime is 21759850718537. The next prime is 21759850718629. The reversal of 21759850718545 is 54581705895712.

It can be written as a sum of positive squares in 4 ways, for example, as 333755776656 + 21426094941889 = 577716^2 + 4628833^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21759850718545 - 2³ = 21759850718537 is a prime.

It is a super-2 number, since 2×21759850718545² (a number of 27 digits) contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 13552816 + ... + 15073105.

It is an arithmetic number, because the mean of its divisors is an integer number (3263999191245).

Almost surely, 2^{21759850718545} is an apocalyptic number.

It is an amenable number.

21759850718545 is a deficient number, since it is larger than the sum of its proper divisors (4352142811415).

21759850718545 is a wasteful number, since it uses less digits than its factorization.

21759850718545 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 28777955.

The product of its (nonzero) digits is 141120000, while the sum is 67.

The spelling of 21759850718545 in words is "twenty-one trillion, seven hundred fifty-nine billion, eight hundred fifty million, seven hundred eighteen thousand, five hundred forty-five".