1690738121 has 2 divisors, whose sum is σ = 1690738122. Its totient is φ = 1690738120.

The previous prime is 1690738117. The next prime is 1690738141. The reversal of 1690738121 is 1218370961.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1665537721 + 25200400 = 40811^2 + 5020^2 .

It is a cyclic number.

It is not a de Polignac number, because 1690738121 - 2² = 1690738117 is a prime.

It is a super-4 number, since 4×1690738121⁴ (a number of 38 digits) contains 4444 as substring. Note that it is a super-d number also for d = 2.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (1690738141) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 845369060 + 845369061.

It is an arithmetic number, because the mean of its divisors is an integer number (845369061).

Almost surely, 2^1690738121 is an apocalyptic number.

It is an amenable number.

1690738121 is a deficient number, since it is larger than the sum of its proper divisors (1).

1690738121 is an equidigital number, since it uses as much as digits as its factorization.

1690738121 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 18144, while the sum is 38.

The square root of 1690738121 is about 41118.5860773446. The cubic root of 1690738121 is about 1191.3118130301.

The spelling of 1690738121 in words is "one billion, six hundred ninety million, seven hundred thirty-eight thousand, one hundred twenty-one".