620646641 has 4 divisors (see below), whose sum is σ = 620696484. Its totient is φ = 620596800.

The previous prime is 620646623. The next prime is 620646671. The reversal of 620646641 is 146646026.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 557904400 + 62742241 = 23620^2 + 7921^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-620646641 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (620646671) 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, 11501 + ... + 37061.

It is an arithmetic number, because the mean of its divisors is an integer number (155174121).

Almost surely, 2^620646641 is an apocalyptic number.

It is an amenable number.

620646641 is a deficient number, since it is larger than the sum of its proper divisors (49843).

620646641 is a wasteful number, since it uses less digits than its factorization.

620646641 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 49842.

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

The square root of 620646641 is about 24912.7806757897. The cubic root of 620646641 is about 852.9982426423.

The spelling of 620646641 in words is "six hundred twenty million, six hundred forty-six thousand, six hundred forty-one".