21735531 has 12 divisors (see below), whose sum is σ = 31826808. Its totient is φ = 14291424.

The previous prime is 21735523. The next prime is 21735533. The reversal of 21735531 is 13553712.

It is not a de Polignac number, because 21735531 - 2³ = 21735523 is a prime.

It is a super-2 number, since 2×21735531² = 944866615703922, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21735495 and 21735504.

It is not an unprimeable number, because it can be changed into a prime (21735533) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 15885 + ... + 17198.

It is an arithmetic number, because the mean of its divisors is an integer number (2652234).

Almost surely, 2^21735531 is an apocalyptic number.

21735531 is a deficient number, since it is larger than the sum of its proper divisors (10091277).

21735531 is a wasteful number, since it uses less digits than its factorization.

21735531 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 33162 (or 33159 counting only the distinct ones).

The product of its digits is 3150, while the sum is 27.

The square root of 21735531 is about 4662.1380288447. The cubic root of 21735531 is about 279.0765966900.

The spelling of 21735531 in words is "twenty-one million, seven hundred thirty-five thousand, five hundred thirty-one".