19901811465 has 12 divisors (see below), whose sum is σ = 34496473284. Its totient is φ = 10614299424.

The previous prime is 19901811443. The next prime is 19901811491. The reversal of 19901811465 is 56411810991.

19901811465 is a `hidden beast` number, since 1 + 9 + 9 + 0 + 181 + 1 + 465 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 4981677561 + 14920133904 = 70581^2 + 122148^2 .

It is not a de Polignac number, because 19901811465 - 2⁹ = 19901810953 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45), and also a Moran number because the ratio is a prime number: 442262477 = 19901811465 / (1 + 9 + 9 + 0 + 1 + 8 + 1 + 1 + 4 + 6 + 5).

It is a self number, because there is not a number n which added to its sum of digits gives 19901811465.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 221131194 + ... + 221131283.

It is an arithmetic number, because the mean of its divisors is an integer number (2874706107).

Almost surely, 2^19901811465 is an apocalyptic number.

19901811465 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

19901811465 is a deficient number, since it is larger than the sum of its proper divisors (14594661819).

19901811465 is a wasteful number, since it uses less digits than its factorization.

19901811465 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 442262488 (or 442262485 counting only the distinct ones).

The product of its (nonzero) digits is 77760, while the sum is 45.

The spelling of 19901811465 in words is "nineteen billion, nine hundred one million, eight hundred eleven thousand, four hundred sixty-five".