644562046 has 4 divisors (see below), whose sum is σ = 966843072. Its totient is φ = 322281022.

The previous prime is 644562031. The next prime is 644562047. The reversal of 644562046 is 640265446.

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

It is a super-2 number, since 2×644562046² = 830920462287412232, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 644561996 and 644562014.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (644562047) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 161140510 + ... + 161140513.

It is an arithmetic number, because the mean of its divisors is an integer number (241710768).

Almost surely, 2^644562046 is an apocalyptic number.

644562046 is a deficient number, since it is larger than the sum of its proper divisors (322281026).

644562046 is a wasteful number, since it uses less digits than its factorization.

644562046 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 322281025.

The product of its (nonzero) digits is 138240, while the sum is 37.

The square root of 644562046 is about 25388.2265233316. The cubic root of 644562046 is about 863.8166611658.

The spelling of 644562046 in words is "six hundred forty-four million, five hundred sixty-two thousand, forty-six".