20551211251 has 2 divisors, whose sum is σ = 20551211252. Its totient is φ = 20551211250.

The previous prime is 20551211249. The next prime is 20551211273. The reversal of 20551211251 is 15211215502.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 20551211251 - 2¹ = 20551211249 is a prime.

Together with 20551211249, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (20551211231) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10275605625 + 10275605626.

It is an arithmetic number, because the mean of its divisors is an integer number (10275605626).

Almost surely, 2^20551211251 is an apocalyptic number.

20551211251 is a deficient number, since it is larger than the sum of its proper divisors (1).

20551211251 is an equidigital number, since it uses as much as digits as its factorization.

20551211251 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1000, while the sum is 25.

Adding to 20551211251 its reverse (15211215502), we get a palindrome (35762426753).

The spelling of 20551211251 in words is "twenty billion, five hundred fifty-one million, two hundred eleven thousand, two hundred fifty-one".