20987857147 has 2 divisors, whose sum is σ = 20987857148. Its totient is φ = 20987857146.

The previous prime is 20987857129. The next prime is 20987857153. The reversal of 20987857147 is 74175878902.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 20987857147 - 2¹⁵ = 20987824379 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 20987857091 and 20987857100.

It is not a weakly prime, because it can be changed into another prime (20987851147) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10493928573 + 10493928574.

It is an arithmetic number, because the mean of its divisors is an integer number (10493928574).

Almost surely, 2^20987857147 is an apocalyptic number.

20987857147 is a deficient number, since it is larger than the sum of its proper divisors (1).

20987857147 is an equidigital number, since it uses as much as digits as its factorization.

20987857147 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 7902720, while the sum is 58.

The spelling of 20987857147 in words is "twenty billion, nine hundred eighty-seven million, eight hundred fifty-seven thousand, one hundred forty-seven".