61321220109 has 24 divisors (see below), whose sum is σ = 91074349080. Its totient is φ = 39741466752.

The previous prime is 61321220071. The next prime is 61321220111. The reversal of 61321220109 is 90102212316.

61321220109 is a `hidden beast` number, since 613 + 2 + 12 + 20 + 10 + 9 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 3719780100 + 57601440009 = 60990^2 + 240003^2 .

It is not a de Polignac number, because 61321220109 - 2⁸ = 61321219853 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (61321221109) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 537714 + ... + 641699.

It is an arithmetic number, because the mean of its divisors is an integer number (3794764545).

Almost surely, 2^61321220109 is an apocalyptic number.

It is an amenable number.

61321220109 is a deficient number, since it is larger than the sum of its proper divisors (29753128971).

61321220109 is a wasteful number, since it uses less digits than its factorization.

61321220109 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1179581 (or 1179578 counting only the distinct ones).

The product of its (nonzero) digits is 1296, while the sum is 27.

The spelling of 61321220109 in words is "sixty-one billion, three hundred twenty-one million, two hundred twenty thousand, one hundred nine".