391903640 has 32 divisors (see below), whose sum is σ = 884180880. Its totient is φ = 156335232.

The previous prime is 391903637. The next prime is 391903649. The reversal of 391903640 is 46309193.

It is a self number, because there is not a number n which added to its sum of digits gives 391903640.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (391903649) 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, 1787 + ... + 28053.

Almost surely, 2^391903640 is an apocalyptic number.

It is an amenable number.

391903640 is an abundant number, since it is smaller than the sum of its proper divisors (492277240).

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

391903640 is a wasteful number, since it uses less digits than its factorization.

391903640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 26651 (or 26647 counting only the distinct ones).

The product of its (nonzero) digits is 17496, while the sum is 35.

The square root of 391903640 is about 19796.5562661792. The cubic root of 391903640 is about 731.8011692844.

The spelling of 391903640 in words is "three hundred ninety-one million, nine hundred three thousand, six hundred forty".