20722501 has 4 divisors (see below), whose sum is σ = 21437100. Its totient is φ = 20007904.

The previous prime is 20722453. The next prime is 20722519. The reversal of 20722501 is 10522702.

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 12888100 + 7834401 = 3590^2 + 2799^2 .

It is a cyclic number.

It is not a de Polignac number, because 20722501 - 2²¹ = 18625349 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20722571) 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, 357256 + ... + 357313.

It is an arithmetic number, because the mean of its divisors is an integer number (5359275).

Almost surely, 2^20722501 is an apocalyptic number.

It is an amenable number.

20722501 is a deficient number, since it is larger than the sum of its proper divisors (714599).

20722501 is an equidigital number, since it uses as much as digits as its factorization.

20722501 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 714598.

The product of its (nonzero) digits is 280, while the sum is 19.

The square root of 20722501 is about 4552.1973814851. The cubic root of 20722501 is about 274.6717891544.

The spelling of 20722501 in words is "twenty million, seven hundred twenty-two thousand, five hundred one".