690742121 has 2 divisors, whose sum is σ = 690742122. Its totient is φ = 690742120.

The previous prime is 690742111. The next prime is 690742123. The reversal of 690742121 is 121247096.

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., 589518400 + 101223721 = 24280^2 + 10061^2 .

It is a cyclic number.

It is not a de Polignac number, because 690742121 - 2²² = 686547817 is a prime.

Together with 690742123, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (690742123) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 345371060 + 345371061.

It is an arithmetic number, because the mean of its divisors is an integer number (345371061).

Almost surely, 2^690742121 is an apocalyptic number.

It is an amenable number.

690742121 is a deficient number, since it is larger than the sum of its proper divisors (1).

690742121 is an equidigital number, since it uses as much as digits as its factorization.

690742121 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 6048, while the sum is 32.

The square root of 690742121 is about 26281.9733087149. The cubic root of 690742121 is about 883.9722803597.

The spelling of 690742121 in words is "six hundred ninety million, seven hundred forty-two thousand, one hundred twenty-one".