2151999 has 12 divisors (see below), whose sum is σ = 3130296. Its totient is φ = 1424592.

The previous prime is 2151991. The next prime is 2152001. The reversal of 2151999 is 9991512.

It is not a de Polignac number, because 2151999 - 2³ = 2151991 is a prime.

2151999 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2151991) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 652 + ... + 2174.

It is an arithmetic number, because the mean of its divisors is an integer number (260858).

2^2151999 is an apocalyptic number.

2151999 is a deficient number, since it is larger than the sum of its proper divisors (978297).

2151999 is a wasteful number, since it uses less digits than its factorization.

2151999 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1686 (or 1683 counting only the distinct ones).

The product of its digits is 7290, while the sum is 36.

The square root of 2151999 is about 1466.9693248327. The cubic root of 2151999 is about 129.1062762209.

The spelling of 2151999 in words is "two million, one hundred fifty-one thousand, nine hundred ninety-nine".