1245553861 has 2 divisors, whose sum is σ = 1245553862. Its totient is φ = 1245553860.

The previous prime is 1245553849. The next prime is 1245553877. The reversal of 1245553861 is 1683555421.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 858841636 + 386712225 = 29306^2 + 19665^2 .

It is an emirp because it is prime and its reverse (1683555421) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1245553861 - 2⁷ = 1245553733 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1245553261) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 622776930 + 622776931.

It is an arithmetic number, because the mean of its divisors is an integer number (622776931).

Almost surely, 2^1245553861 is an apocalyptic number.

It is an amenable number.

1245553861 is a deficient number, since it is larger than the sum of its proper divisors (1).

1245553861 is an equidigital number, since it uses as much as digits as its factorization.

1245553861 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 144000, while the sum is 40.

The square root of 1245553861 is about 35292.4051461501. The cubic root of 1245553861 is about 1075.9386389210.

The spelling of 1245553861 in words is "one billion, two hundred forty-five million, five hundred fifty-three thousand, eight hundred sixty-one".