861981013 has 2 divisors, whose sum is σ = 861981014. Its totient is φ = 861981012.

The previous prime is 861980921. The next prime is 861981017. The reversal of 861981013 is 310189168.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 616181329 + 245799684 = 24823^2 + 15678^2 .

It is a cyclic number.

It is not a de Polignac number, because 861981013 - 2¹³ = 861972821 is a prime.

It is a super-2 number, since 2×861981013² = 1486022533545012338, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (861981017) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 430990506 + 430990507.

It is an arithmetic number, because the mean of its divisors is an integer number (430990507).

Almost surely, 2^861981013 is an apocalyptic number.

It is an amenable number.

861981013 is a deficient number, since it is larger than the sum of its proper divisors (1).

861981013 is an equidigital number, since it uses as much as digits as its factorization.

861981013 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 10368, while the sum is 37.

The square root of 861981013 is about 29359.5131601326. The cubic root of 861981013 is about 951.6981678106.

The spelling of 861981013 in words is "eight hundred sixty-one million, nine hundred eighty-one thousand, thirteen".