690112021 has 2 divisors, whose sum is σ = 690112022. Its totient is φ = 690112020.

The previous prime is 690112019. The next prime is 690112039. The reversal of 690112021 is 120211096.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 395612100 + 294499921 = 19890^2 + 17161^2 .

It is a cyclic number.

It is not a de Polignac number, because 690112021 - 2¹ = 690112019 is a prime.

Together with 690112019, it forms a pair of twin primes.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 690111983 and 690112001.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (690112001) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 345056010 + 345056011.

It is an arithmetic number, because the mean of its divisors is an integer number (345056011).

Almost surely, 2^690112021 is an apocalyptic number.

It is an amenable number.

690112021 is a deficient number, since it is larger than the sum of its proper divisors (1).

690112021 is an equidigital number, since it uses as much as digits as its factorization.

690112021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 216, while the sum is 22.

The square root of 690112021 is about 26269.9832698843. The cubic root of 690112021 is about 883.7034099344.

The spelling of 690112021 in words is "six hundred ninety million, one hundred twelve thousand, twenty-one".