21011511233 has 8 divisors (see below), whose sum is σ = 22552243848. Its totient is φ = 19504641024.

The previous prime is 21011511229. The next prime is 21011511239. The reversal of 21011511233 is 33211511012.

It can be written as a sum of positive squares in 4 ways, for example, as 5412250624 + 15599260609 = 73568^2 + 124897^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21011511233 - 2² = 21011511229 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21011511239) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 8464316 + ... + 8466797.

It is an arithmetic number, because the mean of its divisors is an integer number (2819030481).

Almost surely, 2^21011511233 is an apocalyptic number.

It is an amenable number.

21011511233 is a deficient number, since it is larger than the sum of its proper divisors (1540732615).

21011511233 is a wasteful number, since it uses less digits than its factorization.

21011511233 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16931203.

The product of its (nonzero) digits is 180, while the sum is 20.

The spelling of 21011511233 in words is "twenty-one billion, eleven million, five hundred eleven thousand, two hundred thirty-three".