20400005251 has 2 divisors, whose sum is σ = 20400005252. Its totient is φ = 20400005250.

The previous prime is 20400005201. The next prime is 20400005267. The reversal of 20400005251 is 15250000402.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 20400005251 - 2²⁷ = 20265787523 is a prime.

It is not a weakly prime, because it can be changed into another prime (20400005201) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10200002625 + 10200002626.

It is an arithmetic number, because the mean of its divisors is an integer number (10200002626).

Almost surely, 2^20400005251 is an apocalyptic number.

20400005251 is a deficient number, since it is larger than the sum of its proper divisors (1).

20400005251 is an equidigital number, since it uses as much as digits as its factorization.

20400005251 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 400, while the sum is 19.

Adding to 20400005251 its reverse (15250000402), we get a palindrome (35650005653).

The spelling of 20400005251 in words is "twenty billion, four hundred million, five thousand, two hundred fifty-one".