61521321020641 has 4 divisors (see below), whose sum is σ = 61521463748500. Its totient is φ = 61521178292784.

The previous prime is 61521321020597. The next prime is 61521321020651. The reversal of 61521321020641 is 14602012312516.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 33759539607616 + 27761781413025 = 5810296^2 + 5268945^2 .

It is a cyclic number.

It is not a de Polignac number, because 61521321020641 - 2²⁹ = 61520784149729 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 61521321020597 and 61521321020606.

It is not an unprimeable number, because it can be changed into a prime (61521321020651) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 70715406 + ... + 71580103.

It is an arithmetic number, because the mean of its divisors is an integer number (15380365937125).

Almost surely, 2^{61521321020641} is an apocalyptic number.

It is an amenable number.

61521321020641 is a deficient number, since it is larger than the sum of its proper divisors (142727859).

61521321020641 is a wasteful number, since it uses less digits than its factorization.

61521321020641 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 142727858.

The product of its (nonzero) digits is 17280, while the sum is 34.

The spelling of 61521321020641 in words is "sixty-one trillion, five hundred twenty-one billion, three hundred twenty-one million, twenty thousand, six hundred forty-one".