21210213512 has 8 divisors (see below), whose sum is σ = 39769150350. Its totient is φ = 10605106752.

The previous prime is 21210213511. The next prime is 21210213553. The reversal of 21210213512 is 21531201212.

It can be written as a sum of positive squares in only one way, i.e., 13555013476 + 7655200036 = 116426^2 + 87494^2 .

It is a tau number, because it is divible by the number of its divisors (8).

It is not an unprimeable number, because it can be changed into a prime (21210213511) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1325638337 + ... + 1325638352.

Almost surely, 2^21210213512 is an apocalyptic number.

It is an amenable number.

21210213512 is a deficient number, since it is larger than the sum of its proper divisors (18558936838).

21210213512 is a wasteful number, since it uses less digits than its factorization.

21210213512 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2651276695 (or 2651276691 counting only the distinct ones).

The product of its (nonzero) digits is 240, while the sum is 20.

Adding to 21210213512 its reverse (21531201212), we get a palindrome (42741414724).

The spelling of 21210213512 in words is "twenty-one billion, two hundred ten million, two hundred thirteen thousand, five hundred twelve".