78420721516 has 12 divisors (see below), whose sum is σ = 137282475400. Its totient is φ = 39197157120.

The previous prime is 78420721493. The next prime is 78420721531. The reversal of 78420721516 is 61512702487.

It is a super-2 number, since 2×78420721516² (a number of 23 digits) contains 22 as substring.

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 3 ways as a sum of consecutive naturals, for example, 3287541 + ... + 3311308.

Almost surely, 2^78420721516 is an apocalyptic number.

It is an amenable number.

78420721516 is a deficient number, since it is larger than the sum of its proper divisors (58861753884).

78420721516 is a wasteful number, since it uses less digits than its factorization.

78420721516 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6601824 (or 6601822 counting only the distinct ones).

The product of its (nonzero) digits is 188160, while the sum is 43.

The spelling of 78420721516 in words is "seventy-eight billion, four hundred twenty million, seven hundred twenty-one thousand, five hundred sixteen".