21122073666 has 12 divisors (see below), whose sum is σ = 45764492982. Its totient is φ = 7040691216.

The previous prime is 21122073647. The next prime is 21122073671. The reversal of 21122073666 is 66637022112.

It can be written as a sum of positive squares in only one way, i.e., 17483450625 + 3638623041 = 132225^2 + 60321^2 .

It is a super-2 number, since 2×21122073666² (a number of 21 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21122073666.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 586724251 + ... + 586724286.

Almost surely, 2^21122073666 is an apocalyptic number.

21122073666 is an abundant number, since it is smaller than the sum of its proper divisors (24642419316).

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

21122073666 is a wasteful number, since it uses less digits than its factorization.

21122073666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1173448545 (or 1173448542 counting only the distinct ones).

The product of its (nonzero) digits is 36288, while the sum is 36.

Adding to 21122073666 its reverse (66637022112), we get a palindrome (87759095778).

The spelling of 21122073666 in words is "twenty-one billion, one hundred twenty-two million, seventy-three thousand, six hundred sixty-six".