20508987 has 8 divisors (see below), whose sum is σ = 28953936. Its totient is φ = 12868352.

The previous prime is 20508941. The next prime is 20508991. The reversal of 20508987 is 78980502.

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 20508987 - 2⁸ = 20508731 is a prime.

It is not an unprimeable number, because it can be changed into a prime (20508907) 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, 201018 + ... + 201119.

It is an arithmetic number, because the mean of its divisors is an integer number (3619242).

Almost surely, 2^20508987 is an apocalyptic number.

20508987 is a deficient number, since it is larger than the sum of its proper divisors (8444949).

20508987 is a wasteful number, since it uses less digits than its factorization.

20508987 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 402157.

The product of its (nonzero) digits is 40320, while the sum is 39.

The square root of 20508987 is about 4528.6849084475. The cubic root of 20508987 is about 273.7251715352.

The spelling of 20508987 in words is "twenty million, five hundred eight thousand, nine hundred eighty-seven".