77121515142 has 96 divisors (see below), whose sum is σ = 201510167040. Its totient is φ = 20839800960.

The previous prime is 77121515077. The next prime is 77121515143. The reversal of 77121515142 is 24151512177.

It is a happy number.

77121515142 is a `hidden beast` number, since 7 + 7 + 121 + 515 + 14 + 2 = 666.

It is a junction number, because it is equal to n+sod(n) for n = 77121515097 and 77121515106.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (77121515143) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 108417 + ... + 407427.

It is an arithmetic number, because the mean of its divisors is an integer number (2099064240).

Almost surely, 2^77121515142 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 77121515142, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (100755083520).

77121515142 is an abundant number, since it is smaller than the sum of its proper divisors (124388651898).

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

77121515142 is a wasteful number, since it uses less digits than its factorization.

77121515142 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 299138 (or 299135 counting only the distinct ones).

The product of its digits is 19600, while the sum is 36.

The spelling of 77121515142 in words is "seventy-seven billion, one hundred twenty-one million, five hundred fifteen thousand, one hundred forty-two".