690896021 has 2 divisors, whose sum is σ = 690896022. Its totient is φ = 690896020.

The previous prime is 690896009. The next prime is 690896033. The reversal of 690896021 is 120698096.

690896021 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a balanced prime because it is at equal distance from previous prime (690896009) and next prime (690896033).

It can be written as a sum of positive squares in only one way, i.e., 492396100 + 198499921 = 22190^2 + 14089^2 .

It is a cyclic number.

It is not a de Polignac number, because 690896021 - 2⁶ = 690895957 is a prime.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 690896021.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (690896071) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 345448010 + 345448011.

It is an arithmetic number, because the mean of its divisors is an integer number (345448011).

Almost surely, 2^690896021 is an apocalyptic number.

It is an amenable number.

690896021 is a deficient number, since it is larger than the sum of its proper divisors (1).

690896021 is an equidigital number, since it uses as much as digits as its factorization.

690896021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 46656, while the sum is 41.

The square root of 690896021 is about 26284.9010079932. The cubic root of 690896021 is about 884.0379262920.

The spelling of 690896021 in words is "six hundred ninety million, eight hundred ninety-six thousand, twenty-one".