861440553 has 18 divisors (see below), whose sum is σ = 1251104634. Its totient is φ = 571171392.

The previous prime is 861440527. The next prime is 861440579. The reversal of 861440553 is 355044168.

It is a happy number.

861440553 is a `hidden beast` number, since 8 + 61 + 4 + 40 + 553 = 666.

It is an interprime number because it is at equal distance from previous prime (861440527) and next prime (861440579).

It can be written as a sum of positive squares in only one way, i.e., 855738009 + 5702544 = 29253^2 + 2388^2 .

It is not a de Polignac number, because 861440553 - 2¹⁷ = 861309481 is a prime.

It is a hoax number, since the sum of its digits (36) coincides with the sum of the digits of its distinct prime factors.

It is not an unprimeable number, because it can be changed into a prime (861440513) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 355201 + ... + 357617.

It is an arithmetic number, because the mean of its divisors is an integer number (69505813).

Almost surely, 2^861440553 is an apocalyptic number.

It is an amenable number.

861440553 is a deficient number, since it is larger than the sum of its proper divisors (389664081).

861440553 is a wasteful number, since it uses less digits than its factorization.

861440553 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2821 (or 2619 counting only the distinct ones).

The product of its (nonzero) digits is 57600, while the sum is 36.

The square root of 861440553 is about 29350.3075452371. The cubic root of 861440553 is about 951.4992220793.

The spelling of 861440553 in words is "eight hundred sixty-one million, four hundred forty thousand, five hundred fifty-three".