21512353012 has 12 divisors (see below), whose sum is σ = 37733967936. Its totient is φ = 10731219320.

The previous prime is 21512353007. The next prime is 21512353013. The reversal of 21512353012 is 21035321512.

It is a super-2 number, since 2×21512353012² (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 (21512353013) 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, 6237358 + ... + 6240805.

It is an arithmetic number, because the mean of its divisors is an integer number (3144497328).

Almost surely, 2^21512353012 is an apocalyptic number.

It is an amenable number.

21512353012 is a deficient number, since it is larger than the sum of its proper divisors (16221614924).

21512353012 is a wasteful number, since it uses less digits than its factorization.

21512353012 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12478598 (or 12478596 counting only the distinct ones).

The product of its (nonzero) digits is 1800, while the sum is 25.

Adding to 21512353012 its reverse (21035321512), we get a palindrome (42547674524).

The spelling of 21512353012 in words is "twenty-one billion, five hundred twelve million, three hundred fifty-three thousand, twelve".