21722153 has 2 divisors, whose sum is σ = 21722154. Its totient is φ = 21722152.

The previous prime is 21722147. The next prime is 21722167. The reversal of 21722153 is 35122712.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 11042329 + 10679824 = 3323^2 + 3268^2 .

It is a cyclic number.

It is not a de Polignac number, because 21722153 - 2²² = 17527849 is a prime.

It is not a weakly prime, because it can be changed into another prime (21712153) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10861076 + 10861077.

It is an arithmetic number, because the mean of its divisors is an integer number (10861077).

Almost surely, 2^21722153 is an apocalyptic number.

It is an amenable number.

21722153 is a deficient number, since it is larger than the sum of its proper divisors (1).

21722153 is an equidigital number, since it uses as much as digits as its factorization.

21722153 is an evil number, because the sum of its binary digits is even.

The product of its digits is 840, while the sum is 23.

The square root of 21722153 is about 4660.7030585524. The cubic root of 21722153 is about 279.0193286627.

Adding to 21722153 its reverse (35122712), we get a palindrome (56844865).

The spelling of 21722153 in words is "twenty-one million, seven hundred twenty-two thousand, one hundred fifty-three".