20778413 has 8 divisors (see below), whose sum is σ = 21567000. Its totient is φ = 19994688.

The previous prime is 20778391. The next prime is 20778449. The reversal of 20778413 is 31487702.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 5396329 + 15382084 = 2323^2 + 3922^2 .

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

It is not a de Polignac number, because 20778413 - 2⁸ = 20778157 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 20778413.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20778473) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 9095 + ... + 11147.

It is an arithmetic number, because the mean of its divisors is an integer number (2695875).

Almost surely, 2^20778413 is an apocalyptic number.

It is an amenable number.

20778413 is a deficient number, since it is larger than the sum of its proper divisors (788587).

20778413 is a wasteful number, since it uses less digits than its factorization.

20778413 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2431.

The product of its (nonzero) digits is 9408, while the sum is 32.

The square root of 20778413 is about 4558.3344546007. The cubic root of 20778413 is about 274.9186007018.

The spelling of 20778413 in words is "twenty million, seven hundred seventy-eight thousand, four hundred thirteen".