21201197261 has 16 divisors (see below), whose sum is σ = 21548419200. Its totient is φ = 20857531968.

The previous prime is 21201197239. The next prime is 21201197299. The reversal of 21201197261 is 16279110212.

It is a cyclic number.

It is not a de Polignac number, because 21201197261 - 2¹⁸ = 21200935117 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21201197231) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 9579191 + ... + 9581403.

It is an arithmetic number, because the mean of its divisors is an integer number (1346776200).

Almost surely, 2^21201197261 is an apocalyptic number.

It is an amenable number.

21201197261 is a deficient number, since it is larger than the sum of its proper divisors (347221939).

21201197261 is a wasteful number, since it uses less digits than its factorization.

21201197261 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2948.

The product of its (nonzero) digits is 3024, while the sum is 32.

The spelling of 21201197261 in words is "twenty-one billion, two hundred one million, one hundred ninety-seven thousand, two hundred sixty-one".