21598261745 has 8 divisors (see below), whose sum is σ = 27442497384. Its totient is φ = 16262220544.

The previous prime is 21598261721. The next prime is 21598261771. The reversal of 21598261745 is 54716289512.

It can be written as a sum of positive squares in 4 ways, for example, as 1735305649 + 19862956096 = 41657^2 + 140936^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 21598261745 - 2¹² = 21598257649 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21598261693 and 21598261702.

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, 127048514 + ... + 127048683.

It is an arithmetic number, because the mean of its divisors is an integer number (3430312173).

Almost surely, 2^21598261745 is an apocalyptic number.

It is an amenable number.

21598261745 is a deficient number, since it is larger than the sum of its proper divisors (5844235639).

21598261745 is a wasteful number, since it uses less digits than its factorization.

21598261745 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 254097219.

The product of its digits is 1209600, while the sum is 50.

The spelling of 21598261745 in words is "twenty-one billion, five hundred ninety-eight million, two hundred sixty-one thousand, seven hundred forty-five".