61356355521 has 4 divisors (see below), whose sum is σ = 81808474032. Its totient is φ = 40904237012.

The previous prime is 61356355519. The next prime is 61356355547. The reversal of 61356355521 is 12555365316.

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 not a de Polignac number, because 61356355521 - 2¹ = 61356355519 is a prime.

It is not an unprimeable number, because it can be changed into a prime (61356359521) 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, 10226059251 + ... + 10226059256.

It is an arithmetic number, because the mean of its divisors is an integer number (20452118508).

Almost surely, 2^61356355521 is an apocalyptic number.

It is an amenable number.

61356355521 is a deficient number, since it is larger than the sum of its proper divisors (20452118511).

61356355521 is a wasteful number, since it uses less digits than its factorization.

61356355521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20452118510.

The product of its digits is 405000, while the sum is 42.

The spelling of 61356355521 in words is "sixty-one billion, three hundred fifty-six million, three hundred fifty-five thousand, five hundred twenty-one".