1945658639 has 4 divisors (see below), whose sum is σ = 1950875256. Its totient is φ = 1940442024.

The previous prime is 1945658591. The next prime is 1945658681. The reversal of 1945658639 is 9368565491.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 9368565491 = 9011 ⋅1039681.

It is a cyclic number.

It is not a de Polignac number, because 1945658639 - 2²⁸ = 1677223183 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1945658699) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2607749 + ... + 2608494.

It is an arithmetic number, because the mean of its divisors is an integer number (487718814).

Almost surely, 2^1945658639 is an apocalyptic number.

1945658639 is a deficient number, since it is larger than the sum of its proper divisors (5216617).

1945658639 is an equidigital number, since it uses as much as digits as its factorization.

1945658639 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5216616.

The product of its digits is 6998400, while the sum is 56.

The square root of 1945658639 is about 44109.6207079589. The cubic root of 1945658639 is about 1248.4051423286.

The spelling of 1945658639 in words is "one billion, nine hundred forty-five million, six hundred fifty-eight thousand, six hundred thirty-nine".