688561031 has 2 divisors, whose sum is σ = 688561032. Its totient is φ = 688561030.

The previous prime is 688561019. The next prime is 688561087. The reversal of 688561031 is 130165886.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 688561031 - 2⁶ = 688560967 is a prime.

It is a super-2 number, since 2×688561031² = 948232586823565922, 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 (688561091) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 344280515 + 344280516.

It is an arithmetic number, because the mean of its divisors is an integer number (344280516).

Almost surely, 2^688561031 is an apocalyptic number.

688561031 is a deficient number, since it is larger than the sum of its proper divisors (1).

688561031 is an equidigital number, since it uses as much as digits as its factorization.

688561031 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 34560, while the sum is 38.

The square root of 688561031 is about 26240.4464710492. The cubic root of 688561031 is about 883.0408879144.

The spelling of 688561031 in words is "six hundred eighty-eight million, five hundred sixty-one thousand, thirty-one".