20987857153 has 2 divisors, whose sum is σ = 20987857154. Its totient is φ = 20987857152.

The previous prime is 20987857147. The next prime is 20987857199. The reversal of 20987857153 is 35175878902.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 15298473969 + 5689383184 = 123687^2 + 75428^2 .

It is a cyclic number.

It is not a de Polignac number, because 20987857153 - 2¹³ = 20987848961 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 20987857094 and 20987857103.

It is not a weakly prime, because it can be changed into another prime (20987857103) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10493928576 + 10493928577.

It is an arithmetic number, because the mean of its divisors is an integer number (10493928577).

Almost surely, 2^20987857153 is an apocalyptic number.

It is an amenable number.

20987857153 is a deficient number, since it is larger than the sum of its proper divisors (1).

20987857153 is an equidigital number, since it uses as much as digits as its factorization.

20987857153 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 4233600, while the sum is 55.

The spelling of 20987857153 in words is "twenty billion, nine hundred eighty-seven million, eight hundred fifty-seven thousand, one hundred fifty-three".