51549220840 has 32 divisors (see below), whose sum is σ = 124907728680. Its totient is φ = 19033558272.

The previous prime is 51549220799. The next prime is 51549220843. The reversal of 51549220840 is 4802294515.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 43283138116 + 8266082724 = 208046^2 + 90918^2 .

It is a super-4 number, since 4×51549220840⁴ (a number of 44 digits) contains 4444 as substring. Note that it is a super-d number also for d = 2.

It is a Harshad number since it is a multiple of its sum of digits (40).

It is a junction number, because it is equal to n+sod(n) for n = 51549220793 and 51549220802.

It is not an unprimeable number, because it can be changed into a prime (51549220843) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 49566039 + ... + 49567078.

Almost surely, 2^51549220840 is an apocalyptic number.

It is an amenable number.

51549220840 is an abundant number, since it is smaller than the sum of its proper divisors (73358507840).

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

51549220840 is a wasteful number, since it uses less digits than its factorization.

51549220840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 99133141 (or 99133137 counting only the distinct ones).

The product of its (nonzero) digits is 115200, while the sum is 40.

The spelling of 51549220840 in words is "fifty-one billion, five hundred forty-nine million, two hundred twenty thousand, eight hundred forty".