21973529 has 2 divisors, whose sum is σ = 21973530. Its totient is φ = 21973528.

The previous prime is 21973463. The next prime is 21973591. The reversal of 21973529 is 92537912.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 11560000 + 10413529 = 3400^2 + 3227^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21973529 is a prime.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 21973492 and 21973501.

It is not a weakly prime, because it can be changed into another prime (21973229) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10986764 + 10986765.

It is an arithmetic number, because the mean of its divisors is an integer number (10986765).

Almost surely, 2^21973529 is an apocalyptic number.

It is an amenable number.

21973529 is a deficient number, since it is larger than the sum of its proper divisors (1).

21973529 is an equidigital number, since it uses as much as digits as its factorization.

21973529 is an evil number, because the sum of its binary digits is even.

The product of its digits is 34020, while the sum is 38.

The square root of 21973529 is about 4687.5930924089. The cubic root of 21973529 is about 280.0915049566.

The spelling of 21973529 in words is "twenty-one million, nine hundred seventy-three thousand, five hundred twenty-nine".