2151491 has 4 divisors (see below), whose sum is σ = 2154432. Its totient is φ = 2148552.

The previous prime is 2151473. The next prime is 2151497. The reversal of 2151491 is 1941512.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 2151491 - 2¹⁸ = 1889347 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2151497) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 590 + ... + 2156.

It is an arithmetic number, because the mean of its divisors is an integer number (538608).

2^2151491 is an apocalyptic number.

2151491 is a deficient number, since it is larger than the sum of its proper divisors (2941).

2151491 is a wasteful number, since it uses less digits than its factorization.

2151491 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2940.

The product of its digits is 360, while the sum is 23.

The square root of 2151491 is about 1466.7961685251. The cubic root of 2151491 is about 129.0961164966.

The spelling of 2151491 in words is "two million, one hundred fifty-one thousand, four hundred ninety-one".