1945265691 has 16 divisors (see below), whose sum is σ = 2661715584. Its totient is φ = 1263005184.

The previous prime is 1945265677. The next prime is 1945265701. The reversal of 1945265691 is 1965625491.

It is not a de Polignac number, because 1945265691 - 2⁵ = 1945265659 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1945265691.

It is not an unprimeable number, because it can be changed into a prime (1945265291) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 23035 + ... + 66491.

It is an arithmetic number, because the mean of its divisors is an integer number (166357224).

Almost surely, 2^1945265691 is an apocalyptic number.

1945265691 is a deficient number, since it is larger than the sum of its proper divisors (716449893).

1945265691 is a wasteful number, since it uses less digits than its factorization.

1945265691 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 43850.

The product of its digits is 583200, while the sum is 48.

The square root of 1945265691 is about 44105.1662620152. The cubic root of 1945265691 is about 1248.3210934411.

The spelling of 1945265691 in words is "one billion, nine hundred forty-five million, two hundred sixty-five thousand, six hundred ninety-one".