65721005 has 48 divisors (see below), whose sum is σ = 97511040. Its totient is φ = 42311808.

The previous prime is 65721001. The next prime is 65721049. The reversal of 65721005 is 50012756.

It is not a de Polignac number, because 65721005 - 2² = 65721001 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (65721001) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 602891 + ... + 602999.

It is an arithmetic number, because the mean of its divisors is an integer number (2031480).

Almost surely, 2^65721005 is an apocalyptic number.

It is an amenable number.

65721005 is a deficient number, since it is larger than the sum of its proper divisors (31790035).

65721005 is a wasteful number, since it uses less digits than its factorization.

65721005 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 258 (or 251 counting only the distinct ones).

The product of its (nonzero) digits is 2100, while the sum is 26.

The square root of 65721005 is about 8106.8492646650. The cubic root of 65721005 is about 403.5537605458.

The spelling of 65721005 in words is "sixty-five million, seven hundred twenty-one thousand, five".