6440254020 has 72 divisors (see below), whose sum is σ = 19620870360. Its totient is φ = 1709890560.

The previous prime is 6440253979. The next prime is 6440254033. The reversal of 6440254020 is 204520446.

6440254020 is a `hidden beast` number, since 64 + 40 + 2 + 540 + 20 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 232074756 + 6208179264 = 15234^2 + 78792^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 36901 + ... + 119340.

Almost surely, 2^6440254020 is an apocalyptic number.

6440254020 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

6440254020 is an abundant number, since it is smaller than the sum of its proper divisors (13180616340).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

6440254020 is a wasteful number, since it uses less digits than its factorization.

6440254020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 156485 (or 156480 counting only the distinct ones).

The product of its (nonzero) digits is 7680, while the sum is 27.

The square root of 6440254020 is about 80251.1932621565. The cubic root of 6440254020 is about 1860.5199552248.

Adding to 6440254020 its reverse (204520446), we get a palindrome (6644774466).

The spelling of 6440254020 in words is "six billion, four hundred forty million, two hundred fifty-four thousand, twenty".