643626253 has 4 divisors (see below), whose sum is σ = 645231708. Its totient is φ = 642020800.

The previous prime is 643626251. The next prime is 643626257. The reversal of 643626253 is 352626346.

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 501849604 + 141776649 = 22402^2 + 11907^2 .

It is a cyclic number.

It is not a de Polignac number, because 643626253 - 2¹ = 643626251 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 (643626251) 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, 802126 + ... + 802927.

It is an arithmetic number, because the mean of its divisors is an integer number (161307927).

Almost surely, 2^643626253 is an apocalyptic number.

It is an amenable number.

643626253 is a deficient number, since it is larger than the sum of its proper divisors (1605455).

643626253 is a wasteful number, since it uses less digits than its factorization.

643626253 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1605454.

The product of its digits is 155520, while the sum is 37.

The square root of 643626253 is about 25369.7901646821. The cubic root of 643626253 is about 863.3984210588.

The spelling of 643626253 in words is "six hundred forty-three million, six hundred twenty-six thousand, two hundred fifty-three".