2078721 has 6 divisors (see below), whose sum is σ = 3002610. Its totient is φ = 1385808.

The previous prime is 2078719. The next prime is 2078723. The reversal of 2078721 is 1278702.

It is an interprime number because it is at equal distance from previous prime (2078719) and next prime (2078723).

It can be written as a sum of positive squares in only one way, i.e., 1718721 + 360000 = 1311^2 + 600^2 .

It is not a de Polignac number, because 2078721 - 2¹ = 2078719 is a prime.

It is an Ulam number.

It is not an unprimeable number, because it can be changed into a prime (2078723) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 115476 + ... + 115493.

It is an arithmetic number, because the mean of its divisors is an integer number (500435).

It is a Proth number, since it is equal to 1015 ⋅ 2¹¹ + 1 and 1015 < 2¹¹.

2^2078721 is an apocalyptic number.

It is an amenable number.

2078721 is a deficient number, since it is larger than the sum of its proper divisors (923889).

2078721 is a wasteful number, since it uses less digits than its factorization.

2078721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 230975 (or 230972 counting only the distinct ones).

The product of its (nonzero) digits is 1568, while the sum is 27.

The square root of 2078721 is about 1441.7770285311. Note that the first 3 decimals coincide. The cubic root of 2078721 is about 127.6239164363.

The spelling of 2078721 in words is "two million, seventy-eight thousand, seven hundred twenty-one".