20981499 has 32 divisors (see below), whose sum is σ = 35473920. Its totient is φ = 10713600.

The previous prime is 20981473. The next prime is 20981507. The reversal of 20981499 is 99418902.

It is not a de Polignac number, because 20981499 - 2⁷ = 20981371 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 20981499.

It is not an unprimeable number, because it can be changed into a prime (20981449) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 13347 + ... + 14835.

It is an arithmetic number, because the mean of its divisors is an integer number (1108560).

Almost surely, 2^20981499 is an apocalyptic number.

20981499 is a deficient number, since it is larger than the sum of its proper divisors (14492421).

20981499 is a wasteful number, since it uses less digits than its factorization.

20981499 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1571.

The product of its (nonzero) digits is 46656, while the sum is 42.

The square root of 20981499 is about 4580.5566255642. The cubic root of 20981499 is about 275.8113734268.

The spelling of 20981499 in words is "twenty million, nine hundred eighty-one thousand, four hundred ninety-nine".