21725111 has 2 divisors, whose sum is σ = 21725112. Its totient is φ = 21725110.

The previous prime is 21725101. The next prime is 21725149. The reversal of 21725111 is 11152712.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21725111 - 2⁶ = 21725047 is a prime.

It is a Sophie Germain prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21725101) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10862555 + 10862556.

It is an arithmetic number, because the mean of its divisors is an integer number (10862556).

Almost surely, 2^21725111 is an apocalyptic number.

21725111 is a deficient number, since it is larger than the sum of its proper divisors (1).

21725111 is an equidigital number, since it uses as much as digits as its factorization.

21725111 is an evil number, because the sum of its binary digits is even.

The product of its digits is 140, while the sum is 20.

The square root of 21725111 is about 4661.0203818477. The cubic root of 21725111 is about 279.0319931794.

Adding to 21725111 its reverse (11152712), we get a palindrome (32877823).

The spelling of 21725111 in words is "twenty-one million, seven hundred twenty-five thousand, one hundred eleven".