21018524 has 12 divisors (see below), whose sum is σ = 37009224. Its totient is φ = 10444464.

The previous prime is 21018523. The next prime is 21018539. The reversal of 21018524 is 42581012.

It is a super-2 number, since 2×21018524² = 883556702277152, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21018524.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21018523) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 15467 + ... + 16770.

It is an arithmetic number, because the mean of its divisors is an integer number (3084102).

Almost surely, 2^21018524 is an apocalyptic number.

It is an amenable number.

21018524 is a deficient number, since it is larger than the sum of its proper divisors (15990700).

21018524 is a wasteful number, since it uses less digits than its factorization.

21018524 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 32404 (or 32402 counting only the distinct ones).

The product of its (nonzero) digits is 640, while the sum is 23.

The square root of 21018524 is about 4584.5963835435. The cubic root of 21018524 is about 275.9735149269.

Adding to 21018524 its reverse (42581012), we get a palindrome (63599536).

The spelling of 21018524 in words is "twenty-one million, eighteen thousand, five hundred twenty-four".