20986515 has 24 divisors (see below), whose sum is σ = 39684528. Its totient is φ = 10175040.

The previous prime is 20986481. The next prime is 20986519. The reversal of 20986515 is 51568902.

It is a happy number.

It is not a de Polignac number, because 20986515 - 2⁷ = 20986387 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 20986515.

It is not an unprimeable number, because it can be changed into a prime (20986519) 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, 20704 + ... + 21693.

It is an arithmetic number, because the mean of its divisors is an integer number (1653522).

Almost surely, 2^20986515 is an apocalyptic number.

20986515 is a deficient number, since it is larger than the sum of its proper divisors (18698013).

20986515 is a wasteful number, since it uses less digits than its factorization.

20986515 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 42419 (or 42416 counting only the distinct ones).

The product of its (nonzero) digits is 21600, while the sum is 36.

The square root of 20986515 is about 4581.1041245534. The cubic root of 20986515 is about 275.8333508781.

The spelling of 20986515 in words is "twenty million, nine hundred eighty-six thousand, five hundred fifteen".