1861478140 has 48 divisors (see below), whose sum is σ = 4021268832. Its totient is φ = 723292416.

The previous prime is 1861478123. The next prime is 1861478141. The reversal of 1861478140 is 418741681.

It is a junction number, because it is equal to n+sod(n) for n = 1861478093 and 1861478102.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1861478141) 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, 558519 + ... + 561841.

It is an arithmetic number, because the mean of its divisors is an integer number (83776434).

Almost surely, 2^1861478140 is an apocalyptic number.

1861478140 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1861478140, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2010634416).

1861478140 is an abundant number, since it is smaller than the sum of its proper divisors (2159790692).

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

1861478140 is a wasteful number, since it uses less digits than its factorization.

1861478140 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4126 (or 4124 counting only the distinct ones).

The product of its (nonzero) digits is 43008, while the sum is 40.

The square root of 1861478140 is about 43144.8506776881. The cubic root of 1861478140 is about 1230.1346361534.

The spelling of 1861478140 in words is "one billion, eight hundred sixty-one million, four hundred seventy-eight thousand, one hundred forty".