3945555641 has 4 divisors (see below), whose sum is σ = 3953400192. Its totient is φ = 3937711092.

The previous prime is 3945555587. The next prime is 3945555661. The reversal of 3945555641 is 1465555493.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 3945555641 - 2¹⁸ = 3945293497 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (3945555661) 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, 3921521 + ... + 3922526.

It is an arithmetic number, because the mean of its divisors is an integer number (988350048).

Almost surely, 2^3945555641 is an apocalyptic number.

It is an amenable number.

3945555641 is a deficient number, since it is larger than the sum of its proper divisors (7844551).

3945555641 is an equidigital number, since it uses as much as digits as its factorization.

3945555641 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7844550.

The product of its digits is 1620000, while the sum is 47.

The square root of 3945555641 is about 62813.6580768864. The cubic root of 3945555641 is about 1580.1660404738.

The spelling of 3945555641 in words is "three billion, nine hundred forty-five million, five hundred fifty-five thousand, six hundred forty-one".