61851531720 has 128 divisors (see below), whose sum is σ = 202487091840. Its totient is φ = 14989578240.

The previous prime is 61851531701. The next prime is 61851531769. The reversal of 61851531720 is 2713515816.

It is a super-3 number, since 3×61851531720³ (a number of 33 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is an unprimeable number.

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 31 ways as a sum of consecutive naturals, for example, 6062944 + ... + 6073136.

It is an arithmetic number, because the mean of its divisors is an integer number (1581930405).

Almost surely, 2^61851531720 is an apocalyptic number.

61851531720 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

61851531720 is an abundant number, since it is smaller than the sum of its proper divisors (140635560120).

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

61851531720 is a wasteful number, since it uses less digits than its factorization.

61851531720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14815 (or 14811 counting only the distinct ones).

The product of its (nonzero) digits is 50400, while the sum is 39.

The spelling of 61851531720 in words is "sixty-one billion, eight hundred fifty-one million, five hundred thirty-one thousand, seven hundred twenty".