20981456 has 10 divisors (see below), whose sum is σ = 40651602. Its totient is φ = 10490720.

The previous prime is 20981449. The next prime is 20981459. The reversal of 20981456 is 65418902.

It can be written as a sum of positive squares in only one way, i.e., 10995856 + 9985600 = 3316^2 + 3160^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20981459) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 655655 + ... + 655686.

Almost surely, 2^20981456 is an apocalyptic number.

It is an amenable number.

20981456 is a deficient number, since it is larger than the sum of its proper divisors (19670146).

20981456 is a wasteful number, since it uses less digits than its factorization.

20981456 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1311349 (or 1311343 counting only the distinct ones).

The product of its (nonzero) digits is 17280, while the sum is 35.

The square root of 20981456 is about 4580.5519318091. The cubic root of 20981456 is about 275.8111850085.

The spelling of 20981456 in words is "twenty million, nine hundred eighty-one thousand, four hundred fifty-six".