861026989 has 2 divisors, whose sum is σ = 861026990. Its totient is φ = 861026988.

The previous prime is 861026987. The next prime is 861027001. The reversal of 861026989 is 989620168.

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., 824666089 + 36360900 = 28717^2 + 6030^2 .

It is a cyclic number.

It is not a de Polignac number, because 861026989 - 2¹ = 861026987 is a prime.

It is a super-2 number, since 2×861026989² = 1482734951572812242, which contains 22 as substring.

Together with 861026987, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (861026987) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 430513494 + 430513495.

It is an arithmetic number, because the mean of its divisors is an integer number (430513495).

Almost surely, 2^861026989 is an apocalyptic number.

It is an amenable number.

861026989 is a deficient number, since it is larger than the sum of its proper divisors (1).

861026989 is an equidigital number, since it uses as much as digits as its factorization.

861026989 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 373248, while the sum is 49.

The square root of 861026989 is about 29343.2613899682. The cubic root of 861026989 is about 951.3469311245.

The spelling of 861026989 in words is "eight hundred sixty-one million, twenty-six thousand, nine hundred eighty-nine".