21531213512 has 16 divisors (see below), whose sum is σ = 40387360860. Its totient is φ = 10761250624.

The previous prime is 21531213499. The next prime is 21531213523.

21531213512 is nontrivially palindromic in base 10.

It can be written as a sum of positive squares in 2 ways, for example, as 19732944676 + 1798268836 = 140474^2 + 42406^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 523463 + ... + 563094.

Almost surely, 2^21531213512 is an apocalyptic number.

It is an amenable number.

21531213512 is a deficient number, since it is larger than the sum of its proper divisors (18856147348).

21531213512 is a wasteful number, since it uses less digits than its factorization.

21531213512 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1089040 (or 1089036 counting only the distinct ones).

The product of its digits is 1800, while the sum is 26.

The spelling of 21531213512 in words is "twenty-one billion, five hundred thirty-one million, two hundred thirteen thousand, five hundred twelve".