64221729 has 32 divisors (see below), whose sum is σ = 105907200. Its totient is φ = 34032960.

The previous prime is 64221713. The next prime is 64221737. The reversal of 64221729 is 92712246.

It is not a de Polignac number, because 64221729 - 2⁴ = 64221713 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (33).

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 64221729.

It is not an unprimeable number, because it can be changed into a prime (64221709) 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, 4212 + ... + 12090.

It is an arithmetic number, because the mean of its divisors is an integer number (3309600).

Almost surely, 2^64221729 is an apocalyptic number.

It is an amenable number.

64221729 is a deficient number, since it is larger than the sum of its proper divisors (41685471).

64221729 is a wasteful number, since it uses less digits than its factorization.

64221729 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7925.

The product of its digits is 12096, while the sum is 33.

The square root of 64221729 is about 8013.8460803786. The cubic root of 64221729 is about 400.4614029802.

It can be divided in two parts, 642217 and 29, that added together give a palindrome (642246).

The spelling of 64221729 in words is "sixty-four million, two hundred twenty-one thousand, seven hundred twenty-nine".