20556078901 has 2 divisors, whose sum is σ = 20556078902. Its totient is φ = 20556078900.

The previous prime is 20556078847. The next prime is 20556078913. The reversal of 20556078901 is 10987065502.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 16345366801 + 4210712100 = 127849^2 + 64890^2 .

It is a cyclic number.

It is not a de Polignac number, because 20556078901 - 2¹³ = 20556070709 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20556078941) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10278039450 + 10278039451.

It is an arithmetic number, because the mean of its divisors is an integer number (10278039451).

Almost surely, 2^20556078901 is an apocalyptic number.

It is an amenable number.

20556078901 is a deficient number, since it is larger than the sum of its proper divisors (1).

20556078901 is an equidigital number, since it uses as much as digits as its factorization.

20556078901 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 151200, while the sum is 43.

The spelling of 20556078901 in words is "twenty billion, five hundred fifty-six million, seventy-eight thousand, nine hundred one".