6440951990 has 64 divisors (see below), whose sum is σ = 13008921408. Its totient is φ = 2275737600.

The previous prime is 6440951969. The next prime is 6440952013. The reversal of 6440951990 is 991590446.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1156292 + ... + 1161848.

It is an arithmetic number, because the mean of its divisors is an integer number (203264397).

Almost surely, 2^6440951990 is an apocalyptic number.

6440951990 is an abundant number, since it is smaller than the sum of its proper divisors (6567969418).

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

6440951990 is a wasteful number, since it uses less digits than its factorization.

6440951990 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5873.

The product of its (nonzero) digits is 349920, while the sum is 47.

The square root of 6440951990 is about 80255.5418024201. The cubic root of 6440951990 is about 1860.5871647997.

The spelling of 6440951990 in words is "six billion, four hundred forty million, nine hundred fifty-one thousand, nine hundred ninety".