21621212612 has 24 divisors (see below), whose sum is σ = 40459509720. Its totient is φ = 10073945600.

The previous prime is 21621212593. The next prime is 21621212617.

21621212612 is nontrivially palindromic in base 10.

It can be written as a sum of positive squares in 4 ways, for example, as 16278187396 + 5343025216 = 127586^2 + 73096^2 .

It is not an unprimeable number, because it can be changed into a prime (21621212617) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1567187 + ... + 1580922.

It is an arithmetic number, because the mean of its divisors is an integer number (1685812905).

Almost surely, 2^21621212612 is an apocalyptic number.

It is an amenable number.

21621212612 is a deficient number, since it is larger than the sum of its proper divisors (18838297108).

21621212612 is a wasteful number, since it uses less digits than its factorization.

21621212612 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3148231 (or 3148229 counting only the distinct ones).

The product of its digits is 1152, while the sum is 26.

The spelling of 21621212612 in words is "twenty-one billion, six hundred twenty-one million, two hundred twelve thousand, six hundred twelve".