21040350243 has 16 divisors (see below), whose sum is σ = 30612992256. Its totient is φ = 12748041440.

The previous prime is 21040350239. The next prime is 21040350277. The reversal of 21040350243 is 34205304012.

It is a cyclic number.

It is not a de Polignac number, because 21040350243 - 2² = 21040350239 is a prime.

It is a super-2 number, since 2×21040350243² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21040350043) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 26005 + ... + 206777.

It is an arithmetic number, because the mean of its divisors is an integer number (1913312016).

Almost surely, 2^21040350243 is an apocalyptic number.

21040350243 is a deficient number, since it is larger than the sum of its proper divisors (9572642013).

21040350243 is a wasteful number, since it uses less digits than its factorization.

21040350243 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 184314.

The product of its (nonzero) digits is 2880, while the sum is 24.

Adding to 21040350243 its reverse (34205304012), we get a palindrome (55245654255).

The spelling of 21040350243 in words is "twenty-one billion, forty million, three hundred fifty thousand, two hundred forty-three".