21123411015 has 64 divisors (see below), whose sum is σ = 38845440000. Its totient is φ = 9601663104.

The previous prime is 21123410999. The next prime is 21123411053. The reversal of 21123411015 is 51011432112.

It is not a de Polignac number, because 21123411015 - 2⁴ = 21123410999 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a junction number, because it is equal to n+sod(n) for n = 21123410982 and 21123411000.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 18809244 + ... + 18810366.

It is an arithmetic number, because the mean of its divisors is an integer number (606960000).

Almost surely, 2^21123411015 is an apocalyptic number.

21123411015 is a deficient number, since it is larger than the sum of its proper divisors (17722028985).

21123411015 is a wasteful number, since it uses less digits than its factorization.

21123411015 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1996.

The product of its (nonzero) digits is 240, while the sum is 21.

Adding to 21123411015 its reverse (51011432112), we get a palindrome (72134843127).

The spelling of 21123411015 in words is "twenty-one billion, one hundred twenty-three million, four hundred eleven thousand, fifteen".