21633007261 has 4 divisors (see below), whose sum is σ = 21647212992. Its totient is φ = 21618801532.

The previous prime is 21633007217. The next prime is 21633007267. The reversal of 21633007261 is 16270033612.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21633007261 - 2¹⁹ = 21632482973 is a prime.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21633007267) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 7100581 + ... + 7103626.

It is an arithmetic number, because the mean of its divisors is an integer number (5411803248).

Almost surely, 2^21633007261 is an apocalyptic number.

It is an amenable number.

21633007261 is a deficient number, since it is larger than the sum of its proper divisors (14205731).

21633007261 is a wasteful number, since it uses less digits than its factorization.

21633007261 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14205730.

The product of its (nonzero) digits is 9072, while the sum is 31.

The spelling of 21633007261 in words is "twenty-one billion, six hundred thirty-three million, seven thousand, two hundred sixty-one".