21024986 has 4 divisors (see below), whose sum is σ = 31537482. Its totient is φ = 10512492.

The previous prime is 21024961. The next prime is 21025019. The reversal of 21024986 is 68942012.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 20839225 + 185761 = 4565^2 + 431^2 .

It is a super-3 number, since 3×21024986³ (a number of 23 digits) contains 333 as substring.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5256245 + ... + 5256248.

Almost surely, 2^21024986 is an apocalyptic number.

21024986 is a deficient number, since it is larger than the sum of its proper divisors (10512496).

21024986 is a wasteful number, since it uses less digits than its factorization.

21024986 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10512495.

The product of its (nonzero) digits is 6912, while the sum is 32.

The square root of 21024986 is about 4585.3010806271. The cubic root of 21024986 is about 276.0017940792.

Adding to 21024986 its reverse (68942012), we get a palindrome (89966998).

The spelling of 21024986 in words is "twenty-one million, twenty-four thousand, nine hundred eighty-six".