861921587 has 2 divisors, whose sum is σ = 861921588. Its totient is φ = 861921586.

The previous prime is 861921583. The next prime is 861921589. The reversal of 861921587 is 785129168.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 861921587 - 2² = 861921583 is a prime.

It is a super-3 number, since 3×861921587³ (a number of 28 digits) contains 333 as substring.

Together with 861921589, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (861921581) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 430960793 + 430960794.

It is an arithmetic number, because the mean of its divisors is an integer number (430960794).

Almost surely, 2^861921587 is an apocalyptic number.

861921587 is a deficient number, since it is larger than the sum of its proper divisors (1).

861921587 is an equidigital number, since it uses as much as digits as its factorization.

861921587 is an evil number, because the sum of its binary digits is even.

The product of its digits is 241920, while the sum is 47.

The square root of 861921587 is about 29358.5011027471. The cubic root of 861921587 is about 951.6762969054.

The spelling of 861921587 in words is "eight hundred sixty-one million, nine hundred twenty-one thousand, five hundred eighty-seven".