20856474253 has 2 divisors, whose sum is σ = 20856474254. Its totient is φ = 20856474252.

The previous prime is 20856474227. The next prime is 20856474281. The reversal of 20856474253 is 35247465802.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20847605769 + 8868484 = 144387^2 + 2978^2 .

It is a cyclic number.

It is not a de Polignac number, because 20856474253 - 2⁹ = 20856473741 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20856471253) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10428237126 + 10428237127.

It is an arithmetic number, because the mean of its divisors is an integer number (10428237127).

Almost surely, 2^20856474253 is an apocalyptic number.

It is an amenable number.

20856474253 is a deficient number, since it is larger than the sum of its proper divisors (1).

20856474253 is an equidigital number, since it uses as much as digits as its factorization.

20856474253 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1612800, while the sum is 46.

The spelling of 20856474253 in words is "twenty billion, eight hundred fifty-six million, four hundred seventy-four thousand, two hundred fifty-three".