688920901 has 2 divisors, whose sum is σ = 688920902. Its totient is φ = 688920900.

The previous prime is 688920887. The next prime is 688920907. The reversal of 688920901 is 109029886.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 637512001 + 51408900 = 25249^2 + 7170^2 .

It is a cyclic number.

It is not a de Polignac number, because 688920901 - 2⁹ = 688920389 is a prime.

It is a super-2 number, since 2×688920901² = 949224015669303602, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (688920907) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 344460450 + 344460451.

It is an arithmetic number, because the mean of its divisors is an integer number (344460451).

Almost surely, 2^688920901 is an apocalyptic number.

It is an amenable number.

688920901 is a deficient number, since it is larger than the sum of its proper divisors (1).

688920901 is an equidigital number, since it uses as much as digits as its factorization.

688920901 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 62208, while the sum is 43.

The square root of 688920901 is about 26247.3027376148. The cubic root of 688920901 is about 883.1946988159.

The spelling of 688920901 in words is "six hundred eighty-eight million, nine hundred twenty thousand, nine hundred one".