6439902001 has 9 divisors (see below), whose sum is σ = 6974514849. Its totient is φ = 5943561936.

The previous prime is 6439901987. The next prime is 6439902017. The reversal of 6439902001 is 1002099346.

The square root of 6439902001 is 80249.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in 4 ways, for example, as 5041142001 + 1398760000 = 71001^2 + 37400^2 .

It is not a de Polignac number, because 6439902001 - 2²³ = 6431513393 is a prime.

It is a super-3 number, since 3×6439902001³ (a number of 30 digits) contains 333 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (6439902901) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 1040151 + ... + 1046323.

Almost surely, 2^6439902001 is an apocalyptic number.

6439902001 is the 80249-th square number.

6439902001 is the 40125-th centered octagonal number.

It is an amenable number.

6439902001 is a deficient number, since it is larger than the sum of its proper divisors (534612848).

6439902001 is an frugal number, since it uses more digits than its factorization.

6439902001 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12372 (or 6186 counting only the distinct ones).

The product of its (nonzero) digits is 11664, while the sum is 34.

The cubic root of 6439902001 is about 1860.4860564425.

Multiplying 6439902001 by its product of nonzero digits (11664), we get a square (75115016939664 = 8666892²).

The spelling of 6439902001 in words is "six billion, four hundred thirty-nine million, nine hundred two thousand, one".