64021505 has 4 divisors (see below), whose sum is σ = 76825812. Its totient is φ = 51217200.

The previous prime is 64021501. The next prime is 64021543. The reversal of 64021505 is 50512046.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 11950849 + 52070656 = 3457^2 + 7216^2 .

It is not a de Polignac number, because 64021505 - 2² = 64021501 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (64021501) 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, 6402146 + ... + 6402155.

It is an arithmetic number, because the mean of its divisors is an integer number (19206453).

Almost surely, 2^64021505 is an apocalyptic number.

It is an amenable number.

64021505 is a deficient number, since it is larger than the sum of its proper divisors (12804307).

64021505 is a wasteful number, since it uses less digits than its factorization.

64021505 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12804306.

The product of its (nonzero) digits is 1200, while the sum is 23.

The square root of 64021505 is about 8001.3439496125. The cubic root of 64021505 is about 400.0447970662.

The spelling of 64021505 in words is "sixty-four million, twenty-one thousand, five hundred five".