21530572031 has 2 divisors, whose sum is σ = 21530572032. Its totient is φ = 21530572030.

The previous prime is 21530572013. The next prime is 21530572079. The reversal of 21530572031 is 13027503512.

Together with previous prime (21530572013) it forms an Ormiston pair, because they use the same digits, order apart.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21530572031 - 2²² = 21526377727 is a prime.

It is a super-2 number, since 2×21530572031² (a number of 21 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21530571985 and 21530572003.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21530577031) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10765286015 + 10765286016.

It is an arithmetic number, because the mean of its divisors is an integer number (10765286016).

Almost surely, 2^21530572031 is an apocalyptic number.

21530572031 is a deficient number, since it is larger than the sum of its proper divisors (1).

21530572031 is an equidigital number, since it uses as much as digits as its factorization.

21530572031 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 6300, while the sum is 29.

The spelling of 21530572031 in words is "twenty-one billion, five hundred thirty million, five hundred seventy-two thousand, thirty-one".