21501212210653 has 12 divisors (see below), whose sum is σ = 25011689789820. Its totient is φ = 18429554771712.

The previous prime is 21501212210629. The next prime is 21501212210767. The reversal of 21501212210653 is 35601221210512.

It can be written as a sum of positive squares in 2 ways, for example, as 6563628793764 + 14937583416889 = 2561958^2 + 3864917^2 .

It is a de Polignac number, because none of the positive numbers 2^k-21501212210653 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21501212210053) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 30748333 + ... + 31439821.

It is an arithmetic number, because the mean of its divisors is an integer number (2084307482485).

Almost surely, 2^{21501212210653} is an apocalyptic number.

It is an amenable number.

21501212210653 is a deficient number, since it is larger than the sum of its proper divisors (3510477579167).

21501212210653 is an equidigital number, since it uses as much as digits as its factorization.

21501212210653 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1326076 (or 1326069 counting only the distinct ones).

The product of its (nonzero) digits is 7200, while the sum is 31.

The spelling of 21501212210653 in words is "twenty-one trillion, five hundred one billion, two hundred twelve million, two hundred ten thousand, six hundred fifty-three".