21357529 has 2 divisors, whose sum is σ = 21357530. Its totient is φ = 21357528.

The previous prime is 21357517. The next prime is 21357563. The reversal of 21357529 is 92575312.

It is an a-pointer prime, because the next prime (21357563) can be obtained adding 21357529 to its sum of digits (34).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 11289600 + 10067929 = 3360^2 + 3173^2 .

It is a cyclic number.

It is not a de Polignac number, because 21357529 - 2¹³ = 21349337 is a prime.

It is a super-2 number, since 2×21357529² = 912288089971682, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21357494 and 21357503.

It is not a weakly prime, because it can be changed into another prime (21357509) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10678764 + 10678765.

It is an arithmetic number, because the mean of its divisors is an integer number (10678765).

Almost surely, 2^21357529 is an apocalyptic number.

It is an amenable number.

21357529 is a deficient number, since it is larger than the sum of its proper divisors (1).

21357529 is an equidigital number, since it uses as much as digits as its factorization.

21357529 is an evil number, because the sum of its binary digits is even.

The product of its digits is 18900, while the sum is 34.

The square root of 21357529 is about 4621.4206690151. The cubic root of 21357529 is about 277.4493222393.

It can be divided in two parts, 2 and 1357529, that added together give a palindrome (1357531).

The spelling of 21357529 in words is "twenty-one million, three hundred fifty-seven thousand, five hundred twenty-nine".