697878821 has 2 divisors, whose sum is σ = 697878822. Its totient is φ = 697878820.

The previous prime is 697878817. The next prime is 697878833. The reversal of 697878821 is 128878796.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 692426596 + 5452225 = 26314^2 + 2335^2 .

It is a cyclic number.

It is not a de Polignac number, because 697878821 - 2² = 697878817 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (697878221) 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 as a sum of consecutive naturals, namely, 348939410 + 348939411.

It is an arithmetic number, because the mean of its divisors is an integer number (348939411).

Almost surely, 2^697878821 is an apocalyptic number.

It is an amenable number.

697878821 is a deficient number, since it is larger than the sum of its proper divisors (1).

697878821 is an equidigital number, since it uses as much as digits as its factorization.

697878821 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2709504, while the sum is 56.

The square root of 697878821 is about 26417.3961813045. The cubic root of 697878821 is about 887.0062355857.

The spelling of 697878821 in words is "six hundred ninety-seven million, eight hundred seventy-eight thousand, eight hundred twenty-one".