61520185537 has 4 divisors (see below), whose sum is σ = 61603434160. Its totient is φ = 61436936916.

The previous prime is 61520185483. The next prime is 61520185553. The reversal of 61520185537 is 73558102516.

It is a happy number.

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 61520185537 - 2⁷ = 61520185409 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 61520185493 and 61520185502.

It is not an unprimeable number, because it can be changed into a prime (61520185567) 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, 41623203 + ... + 41624680.

It is an arithmetic number, because the mean of its divisors is an integer number (15400858540).

Almost surely, 2^61520185537 is an apocalyptic number.

It is an amenable number.

61520185537 is a deficient number, since it is larger than the sum of its proper divisors (83248623).

61520185537 is an equidigital number, since it uses as much as digits as its factorization.

61520185537 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 83248622.

The product of its (nonzero) digits is 252000, while the sum is 43.

The spelling of 61520185537 in words is "sixty-one billion, five hundred twenty million, one hundred eighty-five thousand, five hundred thirty-seven".