20987838 has 12 divisors (see below), whose sum is σ = 45473688. Its totient is φ = 6995940.

The previous prime is 20987831. The next prime is 20987839. The reversal of 20987838 is 83878902.

It is a junction number, because it is equal to n+sod(n) for n = 20987793 and 20987802.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20987831) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 582978 + ... + 583013.

It is an arithmetic number, because the mean of its divisors is an integer number (3789474).

Almost surely, 2^20987838 is an apocalyptic number.

20987838 is an abundant number, since it is smaller than the sum of its proper divisors (24485850).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

20987838 is a wasteful number, since it uses less digits than its factorization.

20987838 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1165999 (or 1165996 counting only the distinct ones).

The product of its (nonzero) digits is 193536, while the sum is 45.

The square root of 20987838 is about 4581.2485197815. The cubic root of 20987838 is about 275.8391469787.

The spelling of 20987838 in words is "twenty million, nine hundred eighty-seven thousand, eight hundred thirty-eight".