1212001691 has 2 divisors, whose sum is σ = 1212001692. Its totient is φ = 1212001690.

The previous prime is 1212001673. The next prime is 1212001789. The reversal of 1212001691 is 1961002121.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1212001691 is a prime.

It is not a weakly prime, because it can be changed into another prime (1212001601) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 606000845 + 606000846.

It is an arithmetic number, because the mean of its divisors is an integer number (606000846).

Almost surely, 2^1212001691 is an apocalyptic number.

1212001691 is a deficient number, since it is larger than the sum of its proper divisors (1).

1212001691 is an equidigital number, since it uses as much as digits as its factorization.

1212001691 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 23.

The square root of 1212001691 is about 34813.8146574029. The cubic root of 1212001691 is about 1066.1895181118.

The spelling of 1212001691 in words is "one billion, two hundred twelve million, one thousand, six hundred ninety-one".