861436409 has 8 divisors (see below), whose sum is σ = 870539880. Its totient is φ = 852374016.

The previous prime is 861436391. The next prime is 861436417. The reversal of 861436409 is 904634168.

It can be written as a sum of positive squares in 4 ways, for example, as 12996025 + 848440384 = 3605^2 + 29128^2 .

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-861436409 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (861436439) 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, 32837 + ... + 52925.

It is an arithmetic number, because the mean of its divisors is an integer number (108817485).

Almost surely, 2^861436409 is an apocalyptic number.

It is an amenable number.

861436409 is a deficient number, since it is larger than the sum of its proper divisors (9103471).

861436409 is a wasteful number, since it uses less digits than its factorization.

861436409 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20539.

The product of its (nonzero) digits is 124416, while the sum is 41.

The square root of 861436409 is about 29350.2369496398. The cubic root of 861436409 is about 951.4976963331.

The spelling of 861436409 in words is "eight hundred sixty-one million, four hundred thirty-six thousand, four hundred nine".