24315721 has 4 divisors (see below), whose sum is σ = 24450244. Its totient is φ = 24181200.

The previous prime is 24315703. The next prime is 24315743. The reversal of 24315721 is 12751342.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 12751342 = 2 ⋅6375671.

It can be written as a sum of positive squares in 2 ways, for example, as 7209225 + 17106496 = 2685^2 + 4136^2 .

It is a cyclic number.

It is not a de Polignac number, because 24315721 - 2¹³ = 24307529 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (24315751) 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, 66990 + ... + 67351.

It is an arithmetic number, because the mean of its divisors is an integer number (6112561).

Almost surely, 2^24315721 is an apocalyptic number.

It is an amenable number.

24315721 is a deficient number, since it is larger than the sum of its proper divisors (134523).

24315721 is a wasteful number, since it uses less digits than its factorization.

24315721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 134522.

The product of its digits is 1680, while the sum is 25.

The square root of 24315721 is about 4931.0973423773. The cubic root of 24315721 is about 289.7092647090.

The spelling of 24315721 in words is "twenty-four million, three hundred fifteen thousand, seven hundred twenty-one".