2155720 has 32 divisors (see below), whose sum is σ = 5544000. Its totient is φ = 739008.

The previous prime is 2155717. The next prime is 2155723. The reversal of 2155720 is 275512.

2155720 = T₂₄₉ + T₂₅₀ + ... + T₃₀₄.

It is an interprime number because it is at equal distance from previous prime (2155717) and next prime (2155723).

It is a junction number, because it is equal to n+sod(n) for n = 2155691 and 2155700.

It is not an unprimeable number, because it can be changed into a prime (2155723) 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, 3570 + ... + 4129.

It is an arithmetic number, because the mean of its divisors is an integer number (173250).

2^2155720 is an apocalyptic number.

2155720 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

2155720 is an abundant number, since it is smaller than the sum of its proper divisors (3388280).

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

2155720 is a wasteful number, since it uses less digits than its factorization.

2155720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7717 (or 7713 counting only the distinct ones).

The product of its (nonzero) digits is 700, while the sum is 22.

The square root of 2155720 is about 1468.2370380834. The cubic root of 2155720 is about 129.1806454983.

The spelling of 2155720 in words is "two million, one hundred fifty-five thousand, seven hundred twenty".