20587221 has 24 divisors (see below), whose sum is σ = 31674240. Its totient is φ = 12840576.

The previous prime is 20587219. The next prime is 20587223. The reversal of 20587221 is 12278502.

It is an interprime number because it is at equal distance from previous prime (20587219) and next prime (20587223).

It is not a de Polignac number, because 20587221 - 2¹ = 20587219 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20587223) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 36286 + ... + 36848.

It is an arithmetic number, because the mean of its divisors is an integer number (1319760).

Almost surely, 2^20587221 is an apocalyptic number.

It is an amenable number.

20587221 is a deficient number, since it is larger than the sum of its proper divisors (11087019).

20587221 is a wasteful number, since it uses less digits than its factorization.

20587221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 825 (or 822 counting only the distinct ones).

The product of its (nonzero) digits is 2240, while the sum is 27.

The square root of 20587221 is about 4537.3142937205. The cubic root of 20587221 is about 274.0727824482.

The spelling of 20587221 in words is "twenty million, five hundred eighty-seven thousand, two hundred twenty-one".