1237661861 has 2 divisors, whose sum is σ = 1237661862. Its totient is φ = 1237661860.

The previous prime is 1237661839. The next prime is 1237661917. The reversal of 1237661861 is 1681667321.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 817616836 + 420045025 = 28594^2 + 20495^2 .

It is a cyclic number.

It is not a de Polignac number, because 1237661861 - 2¹⁸ = 1237399717 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1237661801) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 618830930 + 618830931.

It is an arithmetic number, because the mean of its divisors is an integer number (618830931).

Almost surely, 2^1237661861 is an apocalyptic number.

It is an amenable number.

1237661861 is a deficient number, since it is larger than the sum of its proper divisors (1).

1237661861 is an equidigital number, since it uses as much as digits as its factorization.

1237661861 is an evil number, because the sum of its binary digits is even.

The product of its digits is 72576, while the sum is 41.

The square root of 1237661861 is about 35180.4187155298. The cubic root of 1237661861 is about 1073.6613909079.

The spelling of 1237661861 in words is "one billion, two hundred thirty-seven million, six hundred sixty-one thousand, eight hundred sixty-one".