690878231 has 2 divisors, whose sum is σ = 690878232. Its totient is φ = 690878230.

The previous prime is 690878219. The next prime is 690878269. The reversal of 690878231 is 132878096.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-690878231 is a prime.

It is a super-2 number, since 2×690878231² = 954625460139378722, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (690868231) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 345439115 + 345439116.

It is an arithmetic number, because the mean of its divisors is an integer number (345439116).

Almost surely, 2^690878231 is an apocalyptic number.

690878231 is a deficient number, since it is larger than the sum of its proper divisors (1).

690878231 is an equidigital number, since it uses as much as digits as its factorization.

690878231 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 145152, while the sum is 44.

The square root of 690878231 is about 26284.5625986053. The cubic root of 690878231 is about 884.0303384789.

The spelling of 690878231 in words is "six hundred ninety million, eight hundred seventy-eight thousand, two hundred thirty-one".