21015652241 has 4 divisors (see below), whose sum is σ = 21208456500. Its totient is φ = 20822847984.

The previous prime is 21015652201. The next prime is 21015652291. The reversal of 21015652241 is 14225651012.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 14146723600 + 6868928641 = 118940^2 + 82879^2 .

It is a cyclic number.

It is not a de Polignac number, because 21015652241 - 2²⁶ = 20948543377 is a prime.

It is a super-2 number, since 2×21015652241² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21015652201) 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, 96401966 + ... + 96402183.

It is an arithmetic number, because the mean of its divisors is an integer number (5302114125).

Almost surely, 2^21015652241 is an apocalyptic number.

It is an amenable number.

21015652241 is a deficient number, since it is larger than the sum of its proper divisors (192804259).

21015652241 is a wasteful number, since it uses less digits than its factorization.

21015652241 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 192804258.

The product of its (nonzero) digits is 4800, while the sum is 29.

The spelling of 21015652241 in words is "twenty-one billion, fifteen million, six hundred fifty-two thousand, two hundred forty-one".