1221631949 has 2 divisors, whose sum is σ = 1221631950. Its totient is φ = 1221631948.

The previous prime is 1221631937. The next prime is 1221631963. The reversal of 1221631949 is 9491361221.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1101576100 + 120055849 = 33190^2 + 10957^2 .

It is a cyclic number.

It is not a de Polignac number, because 1221631949 - 2⁸ = 1221631693 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1221631909) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 610815974 + 610815975.

It is an arithmetic number, because the mean of its divisors is an integer number (610815975).

Almost surely, 2^1221631949 is an apocalyptic number.

It is an amenable number.

1221631949 is a deficient number, since it is larger than the sum of its proper divisors (1).

1221631949 is an equidigital number, since it uses as much as digits as its factorization.

1221631949 is an evil number, because the sum of its binary digits is even.

The product of its digits is 23328, while the sum is 38.

The square root of 1221631949 is about 34951.8518679626. The cubic root of 1221631949 is about 1069.0059621350.

The spelling of 1221631949 in words is "one billion, two hundred twenty-one million, six hundred thirty-one thousand, nine hundred forty-nine".