61585731921 has 64 divisors (see below), whose sum is σ = 100921835520. Its totient is φ = 32606945280.

The previous prime is 61585731919. The next prime is 61585731931. The reversal of 61585731921 is 12913758516.

It is not a de Polignac number, because 61585731921 - 2¹ = 61585731919 is a prime.

It is not an unprimeable number, because it can be changed into a prime (61585731931) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 5934225 + ... + 5944593.

It is an arithmetic number, because the mean of its divisors is an integer number (1576903680).

Almost surely, 2^61585731921 is an apocalyptic number.

It is an amenable number.

61585731921 is a deficient number, since it is larger than the sum of its proper divisors (39336103599).

61585731921 is a wasteful number, since it uses less digits than its factorization.

61585731921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10654.

The product of its digits is 453600, while the sum is 48.

The spelling of 61585731921 in words is "sixty-one billion, five hundred eighty-five million, seven hundred thirty-one thousand, nine hundred twenty-one".