65021721 has 8 divisors (see below), whose sum is σ = 86938560. Its totient is φ = 43226352.

The previous prime is 65021701. The next prime is 65021731. The reversal of 65021721 is 12712056.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 65021721 - 2⁵ = 65021689 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 65021691 and 65021700.

It is not an unprimeable number, because it can be changed into a prime (65021701) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 29110 + ... + 31263.

It is an arithmetic number, because the mean of its divisors is an integer number (10867320).

Almost surely, 2^65021721 is an apocalyptic number.

It is an amenable number.

65021721 is a deficient number, since it is larger than the sum of its proper divisors (21916839).

65021721 is a wasteful number, since it uses less digits than its factorization.

65021721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 60735.

The product of its (nonzero) digits is 840, while the sum is 24.

The square root of 65021721 is about 8063.6047150142. The cubic root of 65021721 is about 402.1173576322.

Adding to 65021721 its reverse (12712056), we get a palindrome (77733777).

The spelling of 65021721 in words is "sixty-five million, twenty-one thousand, seven hundred twenty-one".