21625229 has 2 divisors, whose sum is σ = 21625230. Its totient is φ = 21625228.

The previous prime is 21625199. The next prime is 21625231. The reversal of 21625229 is 92252612.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20268004 + 1357225 = 4502^2 + 1165^2 .

It is a cyclic number.

It is not a de Polignac number, because 21625229 - 2⁸ = 21624973 is a prime.

Together with 21625231, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21625729) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10812614 + 10812615.

It is an arithmetic number, because the mean of its divisors is an integer number (10812615).

Almost surely, 2^21625229 is an apocalyptic number.

It is an amenable number.

21625229 is a deficient number, since it is larger than the sum of its proper divisors (1).

21625229 is an equidigital number, since it uses as much as digits as its factorization.

21625229 is an evil number, because the sum of its binary digits is even.

The product of its digits is 4320, while the sum is 29.

The square root of 21625229 is about 4650.2934316019. The cubic root of 21625229 is about 278.6037162037.

The spelling of 21625229 in words is "twenty-one million, six hundred twenty-five thousand, two hundred twenty-nine".