20981455 has 8 divisors (see below), whose sum is σ = 27466704. Its totient is φ = 15259200.

The previous prime is 20981449. The next prime is 20981459. The reversal of 20981455 is 55418902.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 20981455 - 2³ = 20981447 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 20981455.

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

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 190686 + ... + 190795.

It is an arithmetic number, because the mean of its divisors is an integer number (3433338).

Almost surely, 2^20981455 is an apocalyptic number.

20981455 is a deficient number, since it is larger than the sum of its proper divisors (6485249).

20981455 is a wasteful number, since it uses less digits than its factorization.

20981455 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 381497.

The product of its (nonzero) digits is 14400, while the sum is 34.

The square root of 20981455 is about 4580.5518226519. The cubic root of 20981455 is about 275.8111806267.

It can be divided in two parts, 2098 and 1455, that added together give a palindrome (3553).

The spelling of 20981455 in words is "twenty million, nine hundred eighty-one thousand, four hundred fifty-five".