3961394639 has 4 divisors (see below), whose sum is σ = 3967406520. Its totient is φ = 3955382760.

The previous prime is 3961394623. The next prime is 3961394687. The reversal of 3961394639 is 9364931693.

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

It is a cyclic number.

It is not a de Polignac number, because 3961394639 - 2⁴ = 3961394623 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 (3961394039) 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, 3004952 + ... + 3006269.

It is an arithmetic number, because the mean of its divisors is an integer number (991851630).

Almost surely, 2^3961394639 is an apocalyptic number.

3961394639 is a deficient number, since it is larger than the sum of its proper divisors (6011881).

3961394639 is an equidigital number, since it uses as much as digits as its factorization.

3961394639 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6011880.

The product of its digits is 2834352, while the sum is 53.

The square root of 3961394639 is about 62939.6110490047. The cubic root of 3961394639 is about 1582.2776847707.

The spelling of 3961394639 in words is "three billion, nine hundred sixty-one million, three hundred ninety-four thousand, six hundred thirty-nine".