21236571061 has 4 divisors (see below), whose sum is σ = 21238684000. Its totient is φ = 21234458124.

The previous prime is 21236571053. The next prime is 21236571067. The reversal of 21236571061 is 16017563212.

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 21236571061 - 2³ = 21236571053 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 (21236571067) 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, 1041321 + ... + 1061518.

It is an arithmetic number, because the mean of its divisors is an integer number (5309671000).

Almost surely, 2^21236571061 is an apocalyptic number.

It is an amenable number.

21236571061 is a deficient number, since it is larger than the sum of its proper divisors (2112939).

21236571061 is a wasteful number, since it uses less digits than its factorization.

21236571061 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2112938.

The product of its (nonzero) digits is 15120, while the sum is 34.

The spelling of 21236571061 in words is "twenty-one billion, two hundred thirty-six million, five hundred seventy-one thousand, sixty-one".