19426505641 has 9 divisors (see below), whose sum is σ = 19971038199. Its totient is φ = 18896447304.

The previous prime is 19426505633. The next prime is 19426505677. The reversal of 19426505641 is 14650562491.

The square root of 19426505641 is 139379.

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., 17383104025 + 2043401616 = 131845^2 + 45204^2 .

It is not a de Polignac number, because 19426505641 - 2³ = 19426505633 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (19426505621) 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, 5155140 + ... + 5158906.

Almost surely, 2^19426505641 is an apocalyptic number.

19426505641 is the 139379-th square number.

19426505641 is the 69690-th centered octagonal number.

It is an amenable number.

19426505641 is a deficient number, since it is larger than the sum of its proper divisors (544532558).

19426505641 is an frugal number, since it uses more digits than its factorization.

19426505641 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7608 (or 3804 counting only the distinct ones).

The product of its (nonzero) digits is 259200, while the sum is 43.

The spelling of 19426505641 in words is "nineteen billion, four hundred twenty-six million, five hundred five thousand, six hundred forty-one".