644161334 has 4 divisors (see below), whose sum is σ = 966242004. Its totient is φ = 322080666.

The previous prime is 644161327. The next prime is 644161337. The reversal of 644161334 is 433161446.

It is a semiprime because it is the product of two primes.

It is a self number, because there is not a number n which added to its sum of digits gives 644161334.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (644161337) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 161040332 + ... + 161040335.

It is an arithmetic number, because the mean of its divisors is an integer number (241560501).

Almost surely, 2^644161334 is an apocalyptic number.

644161334 is a deficient number, since it is larger than the sum of its proper divisors (322080670).

644161334 is a wasteful number, since it uses less digits than its factorization.

644161334 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 322080669.

The product of its digits is 20736, while the sum is 32.

The square root of 644161334 is about 25380.3336069485. Note that the first 3 decimals coincide. The cubic root of 644161334 is about 863.6376179127.

The spelling of 644161334 in words is "six hundred forty-four million, one hundred sixty-one thousand, three hundred thirty-four".