21531074 has 8 divisors (see below), whose sum is σ = 32316348. Its totient is φ = 10758960.

The previous prime is 21531071. The next prime is 21531101. The reversal of 21531074 is 47013512.

It can be written as a sum of positive squares in 2 ways, for example, as 15155449 + 6375625 = 3893^2 + 2525^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not an unprimeable number, because it can be changed into a prime (21531071) 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, 4364 + ... + 7880.

Almost surely, 2^21531074 is an apocalyptic number.

21531074 is a deficient number, since it is larger than the sum of its proper divisors (10785274).

21531074 is a wasteful number, since it uses less digits than its factorization.

21531074 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6580.

The product of its (nonzero) digits is 840, while the sum is 23.

The square root of 21531074 is about 4640.1588334884. The cubic root of 21531074 is about 278.1987864489.

Adding to 21531074 its reverse (47013512), we get a palindrome (68544586).

The spelling of 21531074 in words is "twenty-one million, five hundred thirty-one thousand, seventy-four".