51060721520 has 80 divisors (see below), whose sum is σ = 123769480032. Its totient is φ = 19572833280.

The previous prime is 51060721493. The next prime is 51060721529. The reversal of 51060721520 is 2512706015.

It is a tau number, because it is divible by the number of its divisors (80).

It is a super-2 number, since 2×51060721520² (a number of 22 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51060721529) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 42290 + ... + 322350.

Almost surely, 2^51060721520 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 51060721520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (61884740016).

51060721520 is an abundant number, since it is smaller than the sum of its proper divisors (72708758512).

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

51060721520 is a wasteful number, since it uses less digits than its factorization.

51060721520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 280170 (or 280164 counting only the distinct ones).

The product of its (nonzero) digits is 4200, while the sum is 29.

The spelling of 51060721520 in words is "fifty-one billion, sixty million, seven hundred twenty-one thousand, five hundred twenty".