21355555147 has 2 divisors, whose sum is σ = 21355555148. Its totient is φ = 21355555146.

The previous prime is 21355555139. The next prime is 21355555163. The reversal of 21355555147 is 74155555312.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21355555147 - 2³ = 21355555139 is a prime.

It is not a weakly prime, because it can be changed into another prime (21355595147) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10677777573 + 10677777574.

It is an arithmetic number, because the mean of its divisors is an integer number (10677777574).

Almost surely, 2^21355555147 is an apocalyptic number.

21355555147 is a deficient number, since it is larger than the sum of its proper divisors (1).

21355555147 is an equidigital number, since it uses as much as digits as its factorization.

21355555147 is an evil number, because the sum of its binary digits is even.

The product of its digits is 525000, while the sum is 43.

The spelling of 21355555147 in words is "twenty-one billion, three hundred fifty-five million, five hundred fifty-five thousand, one hundred forty-seven".