861405390 has 48 divisors (see below), whose sum is σ = 2250318096. Its totient is φ = 228614400.

The previous prime is 861405371. The next prime is 861405397. The reversal of 861405390 is 93504168.

861405390 is a `hidden beast` number, since 8 + 614 + 0 + 5 + 39 + 0 = 666.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (861405397) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 3691 + ... + 41670.

It is an arithmetic number, because the mean of its divisors is an integer number (46881627).

Almost surely, 2^861405390 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 861405390, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1125159048).

861405390 is an abundant number, since it is smaller than the sum of its proper divisors (1388912706).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

861405390 is a wasteful number, since it uses less digits than its factorization.

861405390 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 45585 (or 45582 counting only the distinct ones).

The product of its (nonzero) digits is 25920, while the sum is 36.

The square root of 861405390 is about 29349.7085164402. The cubic root of 861405390 is about 951.4862755398.

The spelling of 861405390 in words is "eight hundred sixty-one million, four hundred five thousand, three hundred ninety".