644420337 has 32 divisors (see below), whose sum is σ = 963532800. Its totient is φ = 379753920.

The previous prime is 644420327. The next prime is 644420347. The reversal of 644420337 is 733024446.

It is an interprime number because it is at equal distance from previous prime (644420327) and next prime (644420347).

It is not a de Polignac number, because 644420337 - 2¹¹ = 644418289 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (33).

It is a junction number, because it is equal to n+sod(n) for n = 644420298 and 644420307.

It is not an unprimeable number, because it can be changed into a prime (644420327) 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, 251539 + ... + 254087.

It is an arithmetic number, because the mean of its divisors is an integer number (30110400).

Almost surely, 2^644420337 is an apocalyptic number.

It is an amenable number.

644420337 is a deficient number, since it is larger than the sum of its proper divisors (319112463).

644420337 is a wasteful number, since it uses less digits than its factorization.

644420337 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2773.

The product of its (nonzero) digits is 48384, while the sum is 33.

The square root of 644420337 is about 25385.4355290588. The cubic root of 644420337 is about 863.7533522530.

The spelling of 644420337 in words is "six hundred forty-four million, four hundred twenty thousand, three hundred thirty-seven".