2015921 has 2 divisors, whose sum is σ = 2015922. Its totient is φ = 2015920.

The previous prime is 2015879. The next prime is 2015933. The reversal of 2015921 is 1295102.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1575025 + 440896 = 1255^2 + 664^2 .

It is a cyclic number.

It is not a de Polignac number, because 2015921 - 2¹⁰ = 2014897 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 2015893 and 2015902.

It is not a weakly prime, because it can be changed into another prime (2015941) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1007960 + 1007961.

It is an arithmetic number, because the mean of its divisors is an integer number (1007961).

2^2015921 is an apocalyptic number.

It is an amenable number.

2015921 is a deficient number, since it is larger than the sum of its proper divisors (1).

2015921 is an equidigital number, since it uses as much as digits as its factorization.

2015921 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 180, while the sum is 20.

The square root of 2015921 is about 1419.8313280105. The cubic root of 2015921 is about 126.3255418244.

The spelling of 2015921 in words is "two million, fifteen thousand, nine hundred twenty-one".