644920354 has 8 divisors (see below), whose sum is σ = 1041794460. Its totient is φ = 297655536.

The previous prime is 644920349. The next prime is 644920387. The reversal of 644920354 is 453029446.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 510986025 + 133934329 = 22605^2 + 11573^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 12402289 + ... + 12402340.

Almost surely, 2^644920354 is an apocalyptic number.

644920354 is a deficient number, since it is larger than the sum of its proper divisors (396874106).

644920354 is a wasteful number, since it uses less digits than its factorization.

644920354 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 24804644.

The product of its (nonzero) digits is 103680, while the sum is 37.

The square root of 644920354 is about 25395.2821208980. The cubic root of 644920354 is about 863.9766949375.

The spelling of 644920354 in words is "six hundred forty-four million, nine hundred twenty thousand, three hundred fifty-four".