20981235 has 32 divisors (see below), whose sum is σ = 37013760. Its totient is φ = 10064000.

The previous prime is 20981231. The next prime is 20981237. The reversal of 20981235 is 53218902.

It is a happy number.

It is not a de Polignac number, because 20981235 - 2² = 20981231 is a prime.

It is not an unprimeable number, because it can be changed into a prime (20981231) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 16036 + ... + 17294.

It is an arithmetic number, because the mean of its divisors is an integer number (1156680).

Almost surely, 2^20981235 is an apocalyptic number.

20981235 is a deficient number, since it is larger than the sum of its proper divisors (16032525).

20981235 is a wasteful number, since it uses less digits than its factorization.

20981235 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1379.

The product of its (nonzero) digits is 4320, while the sum is 30.

The square root of 20981235 is about 4580.5278080151. The cubic root of 20981235 is about 275.8102166218.

It can be divided in two parts, 2098 and 1235, that added together give a palindrome (3333).

The spelling of 20981235 in words is "twenty million, nine hundred eighty-one thousand, two hundred thirty-five".