20400013 has 2 divisors, whose sum is σ = 20400014. Its totient is φ = 20400012.

The previous prime is 20399993. The next prime is 20400019. The reversal of 20400013 is 31000402.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19474569 + 925444 = 4413^2 + 962^2 .

It is a cyclic number.

It is not a de Polignac number, because 20400013 - 2¹³ = 20391821 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20400019) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10200006 + 10200007.

It is an arithmetic number, because the mean of its divisors is an integer number (10200007).

Almost surely, 2^20400013 is an apocalyptic number.

It is an amenable number.

20400013 is a deficient number, since it is larger than the sum of its proper divisors (1).

20400013 is an equidigital number, since it uses as much as digits as its factorization.

20400013 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 24, while the sum is 10.

The square root of 20400013 is about 4516.6373553784. The cubic root of 20400013 is about 273.2394996505.

Adding to 20400013 its reverse (31000402), we get a palindrome (51400415).

The spelling of 20400013 in words is "twenty million, four hundred thousand, thirteen".