1861995144 has 64 divisors (see below), whose sum is σ = 4695926400. Its totient is φ = 615233024.

The previous prime is 1861995143. The next prime is 1861995151. The reversal of 1861995144 is 4415991681.

It is a junction number, because it is equal to n+sod(n) for n = 1861995093 and 1861995102.

It is not an unprimeable number, because it can be changed into a prime (1861995143) 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, 1696804 + ... + 1697900.

It is an arithmetic number, because the mean of its divisors is an integer number (73373850).

Almost surely, 2^1861995144 is an apocalyptic number.

It is an amenable number.

1861995144 is an abundant number, since it is smaller than the sum of its proper divisors (2833931256).

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

1861995144 is a wasteful number, since it uses less digits than its factorization.

1861995144 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1662 (or 1658 counting only the distinct ones).

The product of its digits is 311040, while the sum is 48.

The square root of 1861995144 is about 43150.8417530875. The cubic root of 1861995144 is about 1230.2485108289.

The spelling of 1861995144 in words is "one billion, eight hundred sixty-one million, nine hundred ninety-five thousand, one hundred forty-four".