71721423 has 32 divisors (see below), whose sum is σ = 110584320. Its totient is φ = 45904320.

The previous prime is 71721373. The next prime is 71721491. The reversal of 71721423 is 32412717.

It is a happy number.

It is not a de Polignac number, because 71721423 - 2¹³ = 71713231 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (71721823) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 73686 + ... + 74652.

It is an arithmetic number, because the mean of its divisors is an integer number (3455760).

Almost surely, 2^71721423 is an apocalyptic number.

71721423 is a deficient number, since it is larger than the sum of its proper divisors (38862897).

71721423 is a wasteful number, since it uses less digits than its factorization.

71721423 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1084 (or 1078 counting only the distinct ones).

The product of its digits is 2352, while the sum is 27.

The square root of 71721423 is about 8468.8501580793. The cubic root of 71721423 is about 415.4795308505.

The spelling of 71721423 in words is "seventy-one million, seven hundred twenty-one thousand, four hundred twenty-three".