647920394 has 36 divisors (see below), whose sum is σ = 1101231222. Its totient is φ = 285484320.

The previous prime is 647920381. The next prime is 647920397. The reversal of 647920394 is 493029746.

It can be written as a sum of positive squares in 3 ways, for example, as 384669769 + 263250625 = 19613^2 + 16225^2 .

It is a super-2 number, since 2×647920394² = 839601673922230472, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (647920397) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 2408492 + ... + 2408760.

Almost surely, 2^647920394 is an apocalyptic number.

647920394 is a deficient number, since it is larger than the sum of its proper divisors (453310828).

647920394 is a wasteful number, since it uses less digits than its factorization.

647920394 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 599 (or 319 counting only the distinct ones).

The product of its (nonzero) digits is 326592, while the sum is 44.

The square root of 647920394 is about 25454.2804651791. The cubic root of 647920394 is about 865.3143050174.

The spelling of 647920394 in words is "six hundred forty-seven million, nine hundred twenty thousand, three hundred ninety-four".