61520521735021 has 4 divisors (see below), whose sum is σ = 64195327027872. Its totient is φ = 58845716442172.

The previous prime is 61520521734967. The next prime is 61520521735031. The reversal of 61520521735021 is 12053712502516.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-61520521735021 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 (61520521735031) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (29) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1337402646391 + ... + 1337402646436.

It is an arithmetic number, because the mean of its divisors is an integer number (16048831756968).

Almost surely, 2^{61520521735021} is an apocalyptic number.

It is an amenable number.

61520521735021 is a deficient number, since it is larger than the sum of its proper divisors (2674805292851).

61520521735021 is a wasteful number, since it uses less digits than its factorization.

61520521735021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2674805292850.

The product of its (nonzero) digits is 126000, while the sum is 40.

The spelling of 61520521735021 in words is "sixty-one trillion, five hundred twenty billion, five hundred twenty-one million, seven hundred thirty-five thousand, twenty-one".