6640262621 has 4 divisors (see below), whose sum is σ = 6641043612. Its totient is φ = 6639481632.

The previous prime is 6640262597. The next prime is 6640262623. The reversal of 6640262621 is 1262620466.

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 4559625625 + 2080636996 = 67525^2 + 45614^2 .

It is a cyclic number.

It is not a de Polignac number, because 6640262621 - 2¹⁴ = 6640246237 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 (6640262623) 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, 377600 + ... + 394793.

It is an arithmetic number, because the mean of its divisors is an integer number (1660260903).

Almost surely, 2^6640262621 is an apocalyptic number.

It is an amenable number.

6640262621 is a deficient number, since it is larger than the sum of its proper divisors (780991).

6640262621 is an equidigital number, since it uses as much as digits as its factorization.

6640262621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 780990.

The product of its (nonzero) digits is 41472, while the sum is 35.

The square root of 6640262621 is about 81487.8065786532. The cubic root of 6640262621 is about 1879.5840543696.

The spelling of 6640262621 in words is "six billion, six hundred forty million, two hundred sixty-two thousand, six hundred twenty-one".