641950901 has 4 divisors (see below), whose sum is σ = 646636812. Its totient is φ = 637264992.

The previous prime is 641950879. The next prime is 641950909. The reversal of 641950901 is 109059146.

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 528954001 + 112996900 = 22999^2 + 10630^2 .

It is a cyclic number.

It is not a de Polignac number, because 641950901 - 2²² = 637756597 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 (641950909) 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, 2342750 + ... + 2343023.

It is an arithmetic number, because the mean of its divisors is an integer number (161659203).

Almost surely, 2^641950901 is an apocalyptic number.

It is an amenable number.

641950901 is a deficient number, since it is larger than the sum of its proper divisors (4685911).

641950901 is a wasteful number, since it uses less digits than its factorization.

641950901 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4685910.

The product of its (nonzero) digits is 9720, while the sum is 35.

The square root of 641950901 is about 25336.7500086337. The cubic root of 641950901 is about 862.6486312783.

The spelling of 641950901 in words is "six hundred forty-one million, nine hundred fifty thousand, nine hundred one".