20987318 has 8 divisors (see below), whose sum is σ = 34342920. Its totient is φ = 9539680.

The previous prime is 20987287. The next prime is 20987321. The reversal of 20987318 is 81378902.

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

It is a super-3 number, since 3×20987318³ (a number of 23 digits) contains 333 as substring.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 476963 + ... + 477006.

It is an arithmetic number, because the mean of its divisors is an integer number (4292865).

Almost surely, 2^20987318 is an apocalyptic number.

20987318 is a deficient number, since it is larger than the sum of its proper divisors (13355602).

20987318 is a wasteful number, since it uses less digits than its factorization.

20987318 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 953982.

The product of its (nonzero) digits is 24192, while the sum is 38.

The square root of 20987318 is about 4581.1917663420. The cubic root of 20987318 is about 275.8368688730.

The spelling of 20987318 in words is "twenty million, nine hundred eighty-seven thousand, three hundred eighteen".