644462436 has 24 divisors (see below), whose sum is σ = 1540423584. Its totient is φ = 209581120.

The previous prime is 644462431. The next prime is 644462437. The reversal of 644462436 is 634264446.

It is a nude number because it is divisible by every one of its digits.

It is a junction number, because it is equal to n+sod(n) for n = 644462394 and 644462403.

It is not an unprimeable number, because it can be changed into a prime (644462431) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 654450 + ... + 655433.

It is an arithmetic number, because the mean of its divisors is an integer number (64184316).

Almost surely, 2^644462436 is an apocalyptic number.

It is an amenable number.

644462436 is an abundant number, since it is smaller than the sum of its proper divisors (895961148).

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

644462436 is a wasteful number, since it uses less digits than its factorization.

644462436 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1309931 (or 1309929 counting only the distinct ones).

The product of its digits is 331776, while the sum is 39.

The square root of 644462436 is about 25386.2647114537. The cubic root of 644462436 is about 863.7721610741.

The spelling of 644462436 in words is "six hundred forty-four million, four hundred sixty-two thousand, four hundred thirty-six".