1809961380 has 36 divisors (see below), whose sum is σ = 5490216732. Its totient is φ = 482656320.

The previous prime is 1809961357. The next prime is 1809961411. The reversal of 1809961380 is 831699081.

1809961380 is a `hidden beast` number, since 180 + 9 + 96 + 1 + 380 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 1443392064 + 366569316 = 37992^2 + 19146^2 .

It is a tau number, because it is divible by the number of its divisors (36).

It is a Harshad number since it is a multiple of its sum of digits (45).

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 5027491 + ... + 5027850.

Almost surely, 2^1809961380 is an apocalyptic number.

1809961380 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1809961380 is an abundant number, since it is smaller than the sum of its proper divisors (3680255352).

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

1809961380 is a wasteful number, since it uses less digits than its factorization.

1809961380 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10055356 (or 10055351 counting only the distinct ones).

The product of its (nonzero) digits is 93312, while the sum is 45.

The square root of 1809961380 is about 42543.6408879165. The cubic root of 1809961380 is about 1218.6802399519.

The spelling of 1809961380 in words is "one billion, eight hundred nine million, nine hundred sixty-one thousand, three hundred eighty".