626656421 has 4 divisors (see below), whose sum is σ = 627174252. Its totient is φ = 626138592.

The previous prime is 626656417. The next prime is 626656453. The reversal of 626656421 is 124656626.

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 42902500 + 583753921 = 6550^2 + 24161^2 .

It is a cyclic number.

It is not a de Polignac number, because 626656421 - 2² = 626656417 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (626652421) 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, 257096 + ... + 259521.

It is an arithmetic number, because the mean of its divisors is an integer number (156793563).

Almost surely, 2^626656421 is an apocalyptic number.

It is an amenable number.

626656421 is a deficient number, since it is larger than the sum of its proper divisors (517831).

626656421 is a wasteful number, since it uses less digits than its factorization.

626656421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 517830.

The product of its digits is 103680, while the sum is 38.

The square root of 626656421 is about 25033.1064991942. The cubic root of 626656421 is about 855.7426244046.

The spelling of 626656421 in words is "six hundred twenty-six million, six hundred fifty-six thousand, four hundred twenty-one".