861653551 has 16 divisors (see below), whose sum is σ = 996474528. Its totient is φ = 736358400.

The previous prime is 861653549. The next prime is 861653557. The reversal of 861653551 is 155356168.

It is not a de Polignac number, because 861653551 - 2¹ = 861653549 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (861653557) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 188671 + ... + 193183.

It is an arithmetic number, because the mean of its divisors is an integer number (62279658).

Almost surely, 2^861653551 is an apocalyptic number.

861653551 is a deficient number, since it is larger than the sum of its proper divisors (134820977).

861653551 is a wasteful number, since it uses less digits than its factorization.

861653551 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5562.

The product of its digits is 108000, while the sum is 40.

The square root of 861653551 is about 29353.9358689768. The cubic root of 861653551 is about 951.5776375231.

The spelling of 861653551 in words is "eight hundred sixty-one million, six hundred fifty-three thousand, five hundred fifty-one".