19191857945 has 16 divisors (see below), whose sum is σ = 25657022160. Its totient is φ = 13683742464.

The previous prime is 19191857939. The next prime is 19191857959. The reversal of 19191857945 is 54975819191.

It can be written as a sum of positive squares in 8 ways, for example, as 3459674761 + 15732183184 = 58819^2 + 125428^2 .

It is a cyclic number.

It is not a de Polignac number, because 19191857945 - 2⁴ = 19191857929 is a prime.

It is a super-2 number, since 2×19191857945² (a number of 21 digits) contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 5088794 + ... + 5092563.

It is an arithmetic number, because the mean of its divisors is an integer number (1603563885).

Almost surely, 2^19191857945 is an apocalyptic number.

It is an amenable number.

19191857945 is a deficient number, since it is larger than the sum of its proper divisors (6465164215).

19191857945 is a wasteful number, since it uses less digits than its factorization.

19191857945 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10181404.

The product of its digits is 4082400, while the sum is 59.

The spelling of 19191857945 in words is "nineteen billion, one hundred ninety-one million, eight hundred fifty-seven thousand, nine hundred forty-five".