2115551 has 4 divisors (see below), whose sum is σ = 2118600. Its totient is φ = 2112504.

The previous prime is 2115539. The next prime is 2115571. The reversal of 2115551 is 1555112.

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 a de Polignac number, because none of the positive numbers 2^k-2115551 is a prime.

It is an Ulam number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2115511) 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, 80 + ... + 2058.

It is an arithmetic number, because the mean of its divisors is an integer number (529650).

2^2115551 is an apocalyptic number.

2115551 is a deficient number, since it is larger than the sum of its proper divisors (3049).

2115551 is a wasteful number, since it uses less digits than its factorization.

2115551 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3048.

The product of its digits is 250, while the sum is 20.

The square root of 2115551 is about 1454.4933825907. The cubic root of 2115551 is about 128.3732392155.

The spelling of 2115551 in words is "two million, one hundred fifteen thousand, five hundred fifty-one".