644710170438478 has 16 divisors (see below), whose sum is σ = 1009153460347776. Its totient is φ = 308326847245560.

The previous prime is 644710170438469. The next prime is 644710170438487. The reversal of 644710170438478 is 874834071017446.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (644710170438469) and next prime (644710170438487).

It is a super-2 number, since 2×644710170438478² (a number of 30 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 289777176 + ... + 291993547.

It is an arithmetic number, because the mean of its divisors is an integer number (63072091271736).

Almost surely, 2^{644710170438478} is an apocalyptic number.

644710170438478 is a deficient number, since it is larger than the sum of its proper divisors (364443289909298).

644710170438478 is a wasteful number, since it uses less digits than its factorization.

644710170438478 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 581794839.

The product of its (nonzero) digits is 101154816, while the sum is 64.

The spelling of 644710170438478 in words is "six hundred forty-four trillion, seven hundred ten billion, one hundred seventy million, four hundred thirty-eight thousand, four hundred seventy-eight".