1213149661 has 2 divisors, whose sum is σ = 1213149662. Its totient is φ = 1213149660.

The previous prime is 1213149647. The next prime is 1213149667. The reversal of 1213149661 is 1669413121.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1170050436 + 43099225 = 34206^2 + 6565^2 .

It is a cyclic number.

It is not a de Polignac number, because 1213149661 - 2⁹ = 1213149149 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1213149667) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 606574830 + 606574831.

It is an arithmetic number, because the mean of its divisors is an integer number (606574831).

Almost surely, 2^1213149661 is an apocalyptic number.

It is an amenable number.

1213149661 is a deficient number, since it is larger than the sum of its proper divisors (1).

1213149661 is an equidigital number, since it uses as much as digits as its factorization.

1213149661 is an evil number, because the sum of its binary digits is even.

The product of its digits is 7776, while the sum is 34.

The square root of 1213149661 is about 34830.2980320295. The cubic root of 1213149661 is about 1066.5260323161.

The spelling of 1213149661 in words is "one billion, two hundred thirteen million, one hundred forty-nine thousand, six hundred sixty-one".