644066402 has 8 divisors (see below), whose sum is σ = 1104113856. Its totient is φ = 276028452.

The previous prime is 644066387. The next prime is 644066407. The reversal of 644066402 is 204660446.

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

It is not an unprimeable number, because it can be changed into a prime (644066407) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 23002358 + ... + 23002385.

It is an arithmetic number, because the mean of its divisors is an integer number (138014232).

Almost surely, 2^644066402 is an apocalyptic number.

644066402 is a deficient number, since it is larger than the sum of its proper divisors (460047454).

644066402 is a wasteful number, since it uses less digits than its factorization.

644066402 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 46004752.

The product of its (nonzero) digits is 27648, while the sum is 32.

The square root of 644066402 is about 25378.4633498563. The cubic root of 644066402 is about 863.5951902010.

The spelling of 644066402 in words is "six hundred forty-four million, sixty-six thousand, four hundred two".