21040187 has 8 divisors (see below), whose sum is σ = 24108000. Its totient is φ = 17987904.

The previous prime is 21040183. The next prime is 21040199. The reversal of 21040187 is 78104012.

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

It is a cyclic number.

It is not a de Polignac number, because 21040187 - 2² = 21040183 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21040183) 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, 812 + ... + 6537.

It is an arithmetic number, because the mean of its divisors is an integer number (3013500).

Almost surely, 2^21040187 is an apocalyptic number.

21040187 is a deficient number, since it is larger than the sum of its proper divisors (3067813).

21040187 is an equidigital number, since it uses as much as digits as its factorization.

21040187 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7765.

The product of its (nonzero) digits is 448, while the sum is 23.

The square root of 21040187 is about 4586.9583603953. The cubic root of 21040187 is about 276.0682942038.

Adding to 21040187 its reverse (78104012), we get a palindrome (99144199).

The spelling of 21040187 in words is "twenty-one million, forty thousand, one hundred eighty-seven".