861688477 has 8 divisors (see below), whose sum is σ = 938400120. Its totient is φ = 786466560.

The previous prime is 861688453. The next prime is 861688483. The reversal of 861688477 is 774886168.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 9865881 + 851822596 = 3141^2 + 29186^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 861688477 - 2¹⁵ = 861655709 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 (861688417) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 371224 + ... + 373537.

It is an arithmetic number, because the mean of its divisors is an integer number (117300015).

Almost surely, 2^861688477 is an apocalyptic number.

It is an amenable number.

861688477 is a deficient number, since it is larger than the sum of its proper divisors (76711643).

861688477 is a wasteful number, since it uses less digits than its factorization.

861688477 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 744863.

The product of its digits is 3612672, while the sum is 55.

The square root of 861688477 is about 29354.5307746521. The cubic root of 861688477 is about 951.5904943345.

The spelling of 861688477 in words is "eight hundred sixty-one million, six hundred eighty-eight thousand, four hundred seventy-seven".