21530572036 has 6 divisors (see below), whose sum is σ = 37678501070. Its totient is φ = 10765286016.

The previous prime is 21530572031. The next prime is 21530572079. The reversal of 21530572036 is 63027503512.

It can be written as a sum of positive squares in only one way, i.e., 15099494400 + 6431077636 = 122880^2 + 80194^2 .

It is a junction number, because it is equal to n+sod(n) for n = 21530571992 and 21530572010.

It is not an unprimeable number, because it can be changed into a prime (21530572031) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2691321501 + ... + 2691321508.

Almost surely, 2^21530572036 is an apocalyptic number.

It is an amenable number.

21530572036 is a deficient number, since it is larger than the sum of its proper divisors (16147929034).

21530572036 is a wasteful number, since it uses less digits than its factorization.

21530572036 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5382643013 (or 5382643011 counting only the distinct ones).

The product of its (nonzero) digits is 37800, while the sum is 34.

The spelling of 21530572036 in words is "twenty-one billion, five hundred thirty million, five hundred seventy-two thousand, thirty-six".