6440251653 has 32 divisors (see below), whose sum is σ = 10563870720. Its totient is φ = 3844914480.

The previous prime is 6440251621. The next prime is 6440251663. The reversal of 6440251653 is 3561520446.

6440251653 is a `hidden beast` number, since 644 + 0 + 2 + 5 + 1 + 6 + 5 + 3 = 666.

It is not a de Polignac number, because 6440251653 - 2⁵ = 6440251621 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6440251663) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 141925 + ... + 181722.

It is an arithmetic number, because the mean of its divisors is an integer number (330120960).

Almost surely, 2^6440251653 is an apocalyptic number.

It is an amenable number.

6440251653 is a deficient number, since it is larger than the sum of its proper divisors (4123619067).

6440251653 is a wasteful number, since it uses less digits than its factorization.

6440251653 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 323734 (or 323728 counting only the distinct ones).

The product of its (nonzero) digits is 86400, while the sum is 36.

The square root of 6440251653 is about 80251.1785147109. The cubic root of 6440251653 is about 1860.5197272912.

The spelling of 6440251653 in words is "six billion, four hundred forty million, two hundred fifty-one thousand, six hundred fifty-three".