20913481 has 2 divisors, whose sum is σ = 20913482. Its totient is φ = 20913480.

The previous prime is 20913479. The next prime is 20913493. The reversal of 20913481 is 18431902.

It is a happy number.

20913481 is nontrivially palindromic in base 15.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 13623481 + 7290000 = 3691^2 + 2700^2 .

It is a cyclic number.

It is not a de Polignac number, because 20913481 - 2¹ = 20913479 is a prime.

It is a super-2 number, since 2×20913481² = 874747375074722, which contains 22 as substring.

Together with 20913479, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (20913401) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10456740 + 10456741.

It is an arithmetic number, because the mean of its divisors is an integer number (10456741).

Almost surely, 2^20913481 is an apocalyptic number.

It is an amenable number.

20913481 is a deficient number, since it is larger than the sum of its proper divisors (1).

20913481 is an equidigital number, since it uses as much as digits as its factorization.

20913481 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1728, while the sum is 28.

The square root of 20913481 is about 4573.1259549678. The cubic root of 20913481 is about 275.5130082362.

The spelling of 20913481 in words is "twenty million, nine hundred thirteen thousand, four hundred eighty-one".