61931942820 has 576 divisors, whose sum is σ = 228749875200. Its totient is φ = 13785569280.

The previous prime is 61931942791. The next prime is 61931942833. The reversal of 61931942820 is 2824913916.

61931942820 is a `hidden beast` number, since 6 + 193 + 19 + 428 + 20 = 666.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is an unprimeable number.

It is a polite number, since it can be written in 191 ways as a sum of consecutive naturals, for example, 73815961 + ... + 73816799.

It is an arithmetic number, because the mean of its divisors is an integer number (397135200).

Almost surely, 2^61931942820 is an apocalyptic number.

61931942820 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 61931942820, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (114374937600).

61931942820 is an abundant number, since it is smaller than the sum of its proper divisors (166817932380).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

61931942820 is a wasteful number, since it uses less digits than its factorization.

61931942820 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 945 (or 920 counting only the distinct ones).

The product of its (nonzero) digits is 186624, while the sum is 45.

The spelling of 61931942820 in words is "sixty-one billion, nine hundred thirty-one million, nine hundred forty-two thousand, eight hundred twenty".