21015123411 has 16 divisors (see below), whose sum is σ = 28140456960. Its totient is φ = 13950066720.

The previous prime is 21015123407. The next prime is 21015123421. The reversal of 21015123411 is 11432151012.

It is not a de Polignac number, because 21015123411 - 2² = 21015123407 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21015123421) 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, 646596 + ... + 678318.

It is an arithmetic number, because the mean of its divisors is an integer number (1758778560).

Almost surely, 2^21015123411 is an apocalyptic number.

21015123411 is a deficient number, since it is larger than the sum of its proper divisors (7125333549).

21015123411 is a wasteful number, since it uses less digits than its factorization.

21015123411 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 32666.

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

Adding to 21015123411 its reverse (11432151012), we get a palindrome (32447274423).

The spelling of 21015123411 in words is "twenty-one billion, fifteen million, one hundred twenty-three thousand, four hundred eleven".