691498877 has 2 divisors, whose sum is σ = 691498878. Its totient is φ = 691498876.

The previous prime is 691498861. The next prime is 691498889. The reversal of 691498877 is 778894196.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 355473316 + 336025561 = 18854^2 + 18331^2 .

It is a cyclic number.

It is not a de Polignac number, because 691498877 - 2⁴ = 691498861 is a prime.

It is a super-2 number, since 2×691498877² = 956341393784522258, 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 (691498277) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 345749438 + 345749439.

It is an arithmetic number, because the mean of its divisors is an integer number (345749439).

Almost surely, 2^691498877 is an apocalyptic number.

It is an amenable number.

691498877 is a deficient number, since it is larger than the sum of its proper divisors (1).

691498877 is an equidigital number, since it uses as much as digits as its factorization.

691498877 is an evil number, because the sum of its binary digits is even.

The product of its digits is 6096384, while the sum is 59.

The square root of 691498877 is about 26296.3662318580. The cubic root of 691498877 is about 884.2949802313.

The spelling of 691498877 in words is "six hundred ninety-one million, four hundred ninety-eight thousand, eight hundred seventy-seven".