1221312977 has 2 divisors, whose sum is σ = 1221312978. Its totient is φ = 1221312976.

The previous prime is 1221312959. The next prime is 1221313007. The reversal of 1221312977 is 7792131221.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 831803281 + 389509696 = 28841^2 + 19736^2 .

It is a cyclic number.

It is not a de Polignac number, because 1221312977 - 2⁸ = 1221312721 is a prime.

It is not a weakly prime, because it can be changed into another prime (1221312947) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 610656488 + 610656489.

It is an arithmetic number, because the mean of its divisors is an integer number (610656489).

Almost surely, 2^1221312977 is an apocalyptic number.

It is an amenable number.

1221312977 is a deficient number, since it is larger than the sum of its proper divisors (1).

1221312977 is an equidigital number, since it uses as much as digits as its factorization.

1221312977 is an evil number, because the sum of its binary digits is even.

The product of its digits is 10584, while the sum is 35.

The square root of 1221312977 is about 34947.2885500435. The cubic root of 1221312977 is about 1068.9129137468.

The spelling of 1221312977 in words is "one billion, two hundred twenty-one million, three hundred twelve thousand, nine hundred seventy-seven".