20451913 has 4 divisors (see below), whose sum is σ = 20461588. Its totient is φ = 20442240.

The previous prime is 20451911. The next prime is 20451917. The reversal of 20451913 is 31915402.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 2064969 + 18386944 = 1437^2 + 4288^2 .

It is a cyclic number.

It is not a de Polignac number, because 20451913 - 2¹ = 20451911 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20451911) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 156 + ... + 6397.

It is an arithmetic number, because the mean of its divisors is an integer number (5115397).

Almost surely, 2^20451913 is an apocalyptic number.

It is an amenable number.

20451913 is a deficient number, since it is larger than the sum of its proper divisors (9675).

20451913 is an equidigital number, since it uses as much as digits as its factorization.

20451913 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9674.

The product of its (nonzero) digits is 1080, while the sum is 25.

The square root of 20451913 is about 4522.3791305020. The cubic root of 20451913 is about 273.4710210855.

The spelling of 20451913 in words is "twenty million, four hundred fifty-one thousand, nine hundred thirteen".