21571266207 has 24 divisors (see below), whose sum is σ = 30008364672. Its totient is φ = 13781640240.

The previous prime is 21571266173. The next prime is 21571266209. The reversal of 21571266207 is 70266217512.

It is not a de Polignac number, because 21571266207 - 2¹⁶ = 21571200671 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21571266209) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 260628 + ... + 333270.

It is an arithmetic number, because the mean of its divisors is an integer number (1250348528).

Almost surely, 2^21571266207 is an apocalyptic number.

21571266207 is a deficient number, since it is larger than the sum of its proper divisors (8437098465).

21571266207 is a wasteful number, since it uses less digits than its factorization.

21571266207 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 72811 (or 72780 counting only the distinct ones).

The product of its (nonzero) digits is 70560, while the sum is 39.

The spelling of 21571266207 in words is "twenty-one billion, five hundred seventy-one million, two hundred sixty-six thousand, two hundred seven".