2187681 has 8 divisors (see below), whose sum is σ = 2972160. Its totient is φ = 1430832.

The previous prime is 2187671. The next prime is 2187683. The reversal of 2187681 is 1867812.

2187681 = T₄₈₄ + T₄₈₅ + ... + T₅₀₁.

It is a happy number.

2187681 is nontrivially palindromic in base 2.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 2187681 - 2¹⁵ = 2154913 is a prime.

It is a super-2 number, since 2×2187681² = 9571896315522, which contains 22 as substring.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (2187683) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6721 + ... + 7038.

It is an arithmetic number, because the mean of its divisors is an integer number (371520).

2^2187681 is an apocalyptic number.

It is an amenable number.

2187681 is a deficient number, since it is larger than the sum of its proper divisors (784479).

2187681 is a wasteful number, since it uses less digits than its factorization.

2187681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13815.

The product of its digits is 5376, while the sum is 33.

The square root of 2187681 is about 1479.0811336773. The cubic root of 2187681 is about 129.8159327958.

The spelling of 2187681 in words is "two million, one hundred eighty-seven thousand, six hundred eighty-one".