64469721 has 4 divisors (see below), whose sum is σ = 85959632. Its totient is φ = 42979812.

The previous prime is 64469719. The next prime is 64469791. The reversal of 64469721 is 12796446.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 64469721 - 2¹ = 64469719 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 64469721.

It is not an unprimeable number, because it can be changed into a prime (64469701) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 10744951 + ... + 10744956.

It is an arithmetic number, because the mean of its divisors is an integer number (21489908).

Almost surely, 2^64469721 is an apocalyptic number.

It is an amenable number.

64469721 is a deficient number, since it is larger than the sum of its proper divisors (21489911).

64469721 is a wasteful number, since it uses less digits than its factorization.

64469721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21489910.

The product of its digits is 72576, while the sum is 39.

The square root of 64469721 is about 8029.3038926173. The cubic root of 64469721 is about 400.9762010573.

The spelling of 64469721 in words is "sixty-four million, four hundred sixty-nine thousand, seven hundred twenty-one".