21145015512 has 96 divisors (see below), whose sum is σ = 57945888000. Its totient is φ = 6965222400.

The previous prime is 21145015511. The next prime is 21145015571. The reversal of 21145015512 is 21551054112.

It is a happy number.

21145015512 is a `hidden beast` number, since 2 + 1 + 145 + 0 + 1 + 5 + 512 = 666.

It is a super-2 number, since 2×21145015512² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21145015511) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 3143689 + ... + 3150407.

It is an arithmetic number, because the mean of its divisors is an integer number (603603000).

Almost surely, 2^21145015512 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21145015512, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28972944000).

21145015512 is an abundant number, since it is smaller than the sum of its proper divisors (36800872488).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21145015512 is a wasteful number, since it uses less digits than its factorization.

21145015512 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7241 (or 7234 counting only the distinct ones).

The product of its (nonzero) digits is 2000, while the sum is 27.

Adding to 21145015512 its reverse (21551054112), we get a palindrome (42696069624).

The spelling of 21145015512 in words is "twenty-one billion, one hundred forty-five million, fifteen thousand, five hundred twelve".