20400023251 has 2 divisors, whose sum is σ = 20400023252. Its totient is φ = 20400023250.

The previous prime is 20400023221. The next prime is 20400023257. The reversal of 20400023251 is 15232000402.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 20400023251 - 2¹³ = 20400015059 is a prime.

It is not a weakly prime, because it can be changed into another prime (20400023257) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10200011625 + 10200011626.

It is an arithmetic number, because the mean of its divisors is an integer number (10200011626).

Almost surely, 2^20400023251 is an apocalyptic number.

20400023251 is a deficient number, since it is larger than the sum of its proper divisors (1).

20400023251 is an equidigital number, since it uses as much as digits as its factorization.

20400023251 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 480, while the sum is 19.

Adding to 20400023251 its reverse (15232000402), we get a palindrome (35632023653).

The spelling of 20400023251 in words is "twenty billion, four hundred million, twenty-three thousand, two hundred fifty-one".