2157780 has 24 divisors (see below), whose sum is σ = 6041952. Its totient is φ = 575392.

The previous prime is 2157769. The next prime is 2157787. The reversal of 2157780 is 877512.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2157787) 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, 17922 + ... + 18041.

It is an arithmetic number, because the mean of its divisors is an integer number (251748).

2^2157780 is an apocalyptic number.

2157780 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

2157780 is an abundant number, since it is smaller than the sum of its proper divisors (3884172).

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

2157780 is a wasteful number, since it uses less digits than its factorization.

2157780 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 35975 (or 35973 counting only the distinct ones).

The product of its (nonzero) digits is 3920, while the sum is 30.

The square root of 2157780 is about 1468.9383921731. The cubic root of 2157780 is about 129.2217806194.

The spelling of 2157780 in words is "two million, one hundred fifty-seven thousand, seven hundred eighty".