2151780 has 24 divisors (see below), whose sum is σ = 6025152. Its totient is φ = 573792.

The previous prime is 2151767. The next prime is 2151781. The reversal of 2151780 is 871512.

It is a self number, because there is not a number n which added to its sum of digits gives 2151780.

It is not an unprimeable number, because it can be changed into a prime (2151781) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 17872 + ... + 17991.

It is an arithmetic number, because the mean of its divisors is an integer number (251048).

2^2151780 is an apocalyptic number.

2151780 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

2151780 is an abundant number, since it is smaller than the sum of its proper divisors (3873372).

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

2151780 is a wasteful number, since it uses less digits than its factorization.

2151780 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 35875 (or 35873 counting only the distinct ones).

The product of its (nonzero) digits is 560, while the sum is 24.

The square root of 2151780 is about 1466.8946792459. The cubic root of 2151780 is about 129.1018965358.

The spelling of 2151780 in words is "two million, one hundred fifty-one thousand, seven hundred eighty".