20272721 has 12 divisors (see below), whose sum is σ = 24970788. Its totient is φ = 16353792.

The previous prime is 20272699. The next prime is 20272741. The reversal of 20272721 is 12727202.

It can be written as a sum of positive squares in 2 ways, for example, as 19018321 + 1254400 = 4361^2 + 1120^2 .

It is not a de Polignac number, because 20272721 - 2⁶ = 20272657 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20272741) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 11336 + ... + 13001.

It is an arithmetic number, because the mean of its divisors is an integer number (2080899).

Almost surely, 2^20272721 is an apocalyptic number.

It is an amenable number.

20272721 is a deficient number, since it is larger than the sum of its proper divisors (4698067).

20272721 is a wasteful number, since it uses less digits than its factorization.

20272721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 24368 (or 24361 counting only the distinct ones).

The product of its (nonzero) digits is 784, while the sum is 23.

The square root of 20272721 is about 4502.5238477991. The cubic root of 20272721 is about 272.6699935298.

Adding to 20272721 its reverse (12727202), we get a palindrome (32999923).

The spelling of 20272721 in words is "twenty million, two hundred seventy-two thousand, seven hundred twenty-one".