3938772661 has 4 divisors (see below), whose sum is σ = 3974908300. Its totient is φ = 3902637024.

The previous prime is 3938772647. The next prime is 3938772667. The reversal of 3938772661 is 1662778393.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 3207070161 + 731702500 = 56631^2 + 27050^2 .

It is a cyclic number.

It is not a de Polignac number, because 3938772661 - 2²³ = 3930384053 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 3938772599 and 3938772608.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (3938772667) 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, 18067656 + ... + 18067873.

It is an arithmetic number, because the mean of its divisors is an integer number (993727075).

Almost surely, 2^3938772661 is an apocalyptic number.

It is an amenable number.

3938772661 is a deficient number, since it is larger than the sum of its proper divisors (36135639).

3938772661 is a wasteful number, since it uses less digits than its factorization.

3938772661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 36135638.

The product of its digits is 2286144, while the sum is 52.

The square root of 3938772661 is about 62759.6419763529. The cubic root of 3938772661 is about 1579.2600098609.

The spelling of 3938772661 in words is "three billion, nine hundred thirty-eight million, seven hundred seventy-two thousand, six hundred sixty-one".