21011512 has 16 divisors (see below), whose sum is σ = 41109840. Its totient is φ = 10048896.

The previous prime is 21011509. The next prime is 21011513. The reversal of 21011512 is 21511012.

It is a super-2 number, since 2×21011512² = 882967273052288, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21011492 and 21011501.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21011513) 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, 56913 + ... + 57280.

It is an arithmetic number, because the mean of its divisors is an integer number (2569365).

Almost surely, 2^21011512 is an apocalyptic number.

It is an amenable number.

21011512 is a deficient number, since it is larger than the sum of its proper divisors (20098328).

21011512 is a wasteful number, since it uses less digits than its factorization.

21011512 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 114222 (or 114218 counting only the distinct ones).

The product of its (nonzero) digits is 20, while the sum is 13.

The square root of 21011512 is about 4583.8315850389. The cubic root of 21011512 is about 275.9428222941.

Adding to 21011512 its reverse (21511012), we get a palindrome (42522524).

Subtracting 21011512 from its reverse (21511012), we obtain a triangular number (499500 = T₉₉₉).

The spelling of 21011512 in words is "twenty-one million, eleven thousand, five hundred twelve".