64722021 has 32 divisors (see below), whose sum is σ = 106659840. Its totient is φ = 33994944.

The previous prime is 64721981. The next prime is 64722029. The reversal of 64722021 is 12022746.

It is not a de Polignac number, because 64722021 - 2⁹ = 64721509 is a prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 64721982 and 64722000.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (64722029) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 104250 + ... + 104868.

It is an arithmetic number, because the mean of its divisors is an integer number (3333120).

Almost surely, 2^64722021 is an apocalyptic number.

It is an amenable number.

64722021 is a deficient number, since it is larger than the sum of its proper divisors (41937819).

64722021 is a wasteful number, since it uses less digits than its factorization.

64722021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1025.

The product of its (nonzero) digits is 1344, while the sum is 24.

The square root of 64722021 is about 8044.9997513984. Note that the first 3 decimals coincide. The cubic root of 64722021 is about 401.4985889829.

Adding to 64722021 its reverse (12022746), we get a palindrome (76744767).

The spelling of 64722021 in words is "sixty-four million, seven hundred twenty-two thousand, twenty-one".