207640391 has 6 divisors (see below), whose sum is σ = 241540920. Its totient is φ = 177977436.

The previous prime is 207640373. The next prime is 207640409. The reversal of 207640391 is 193046702.

It is an interprime number because it is at equal distance from previous prime (207640373) and next prime (207640409).

It is not a de Polignac number, because 207640391 - 2¹⁴ = 207624007 is a prime.

It is a super-2 number, since 2×207640391² = 86229063949265762, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (207643391) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 2118731 + ... + 2118828.

It is an arithmetic number, because the mean of its divisors is an integer number (40256820).

Almost surely, 2^207640391 is an apocalyptic number.

207640391 is a deficient number, since it is larger than the sum of its proper divisors (33900529).

207640391 is an equidigital number, since it uses as much as digits as its factorization.

207640391 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4237573 (or 4237566 counting only the distinct ones).

The product of its (nonzero) digits is 9072, while the sum is 32.

The square root of 207640391 is about 14409.7325096617. The cubic root of 207640391 is about 592.1575615049.

The spelling of 207640391 in words is "two hundred seven million, six hundred forty thousand, three hundred ninety-one".