1242649657 has 2 divisors, whose sum is σ = 1242649658. Its totient is φ = 1242649656.

The previous prime is 1242649649. The next prime is 1242649687. The reversal of 1242649657 is 7569462421.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1206937081 + 35712576 = 34741^2 + 5976^2 .

It is a cyclic number.

It is not a de Polignac number, because 1242649657 - 2³ = 1242649649 is a prime.

It is not a weakly prime, because it can be changed into another prime (1242649627) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 621324828 + 621324829.

It is an arithmetic number, because the mean of its divisors is an integer number (621324829).

Almost surely, 2^1242649657 is an apocalyptic number.

It is an amenable number.

1242649657 is a deficient number, since it is larger than the sum of its proper divisors (1).

1242649657 is an equidigital number, since it uses as much as digits as its factorization.

1242649657 is an evil number, because the sum of its binary digits is even.

The product of its digits is 725760, while the sum is 46.

The square root of 1242649657 is about 35251.2362478254. The cubic root of 1242649657 is about 1075.1017482925.

The spelling of 1242649657 in words is "one billion, two hundred forty-two million, six hundred forty-nine thousand, six hundred fifty-seven".