1861509252 has 12 divisors (see below), whose sum is σ = 4343521616. Its totient is φ = 620503080.

The previous prime is 1861509239. The next prime is 1861509253. The reversal of 1861509252 is 2529051681.

It is a tau number, because it is divible by the number of its divisors (12).

It is a hoax number, since the sum of its digits (39) coincides with the sum of the digits of its distinct prime factors.

It is a self number, because there is not a number n which added to its sum of digits gives 1861509252.

It is not an unprimeable number, because it can be changed into a prime (1861509253) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 77562874 + ... + 77562897.

Almost surely, 2^1861509252 is an apocalyptic number.

1861509252 is a gapful number since it is divisible by the number (12) formed by its first and last digit.

It is an amenable number.

1861509252 is an abundant number, since it is smaller than the sum of its proper divisors (2482012364).

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

1861509252 is a wasteful number, since it uses less digits than its factorization.

1861509252 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 155125778 (or 155125776 counting only the distinct ones).

The product of its (nonzero) digits is 43200, while the sum is 39.

The square root of 1861509252 is about 43145.2112290576. The cubic root of 1861509252 is about 1230.1414894410.

The spelling of 1861509252 in words is "one billion, eight hundred sixty-one million, five hundred nine thousand, two hundred fifty-two".