20020400042491 has 2 divisors, whose sum is σ = 20020400042492. Its totient is φ = 20020400042490.

The previous prime is 20020400042381. The next prime is 20020400042557. The reversal of 20020400042491 is 19424000402002.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 20020400042491 - 2¹⁵ = 20020400009723 is a prime.

It is a super-2 number, since 2×20020400042491² (a number of 27 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (20020400042191) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10010200021245 + 10010200021246.

It is an arithmetic number, because the mean of its divisors is an integer number (10010200021246).

Almost surely, 2^{20020400042491} is an apocalyptic number.

20020400042491 is a deficient number, since it is larger than the sum of its proper divisors (1).

20020400042491 is an equidigital number, since it uses as much as digits as its factorization.

20020400042491 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 4608, while the sum is 28.

Adding to 20020400042491 its reverse (19424000402002), we get a palindrome (39444400444493).

The spelling of 20020400042491 in words is "twenty trillion, twenty billion, four hundred million, forty-two thousand, four hundred ninety-one".