78101721 has 24 divisors (see below), whose sum is σ = 118198080. Its totient is φ = 49601376.

The previous prime is 78101713. The next prime is 78101731. The reversal of 78101721 is 12710187.

It is not a de Polignac number, because 78101721 - 2³ = 78101713 is a prime.

It is a super-3 number, since 3×78101721³ (a number of 25 digits) contains 333 as substring.

It is not an unprimeable number, because it can be changed into a prime (78101731) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 62935 + ... + 64163.

It is an arithmetic number, because the mean of its divisors is an integer number (4924920).

Almost surely, 2^78101721 is an apocalyptic number.

It is an amenable number.

78101721 is a deficient number, since it is larger than the sum of its proper divisors (40096359).

78101721 is a wasteful number, since it uses less digits than its factorization.

78101721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1565 (or 1562 counting only the distinct ones).

The product of its (nonzero) digits is 784, while the sum is 27.

The square root of 78101721 is about 8837.5178076200. The cubic root of 78101721 is about 427.4515221524.

The spelling of 78101721 in words is "seventy-eight million, one hundred one thousand, seven hundred twenty-one".