21612469 has 4 divisors (see below), whose sum is σ = 21625740. Its totient is φ = 21599200.

The previous prime is 21612431. The next prime is 21612497. The reversal of 21612469 is 96421612.

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

It can be written as a sum of positive squares in 2 ways, for example, as 6441444 + 15171025 = 2538^2 + 3895^2 .

It is a cyclic number.

It is not a de Polignac number, because 21612469 - 2⁹ = 21611957 is a prime.

It is a super-2 number, since 2×21612469² = 934197632551922, which contains 22 as substring.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21612469.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21612769) 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, 3784 + ... + 7585.

It is an arithmetic number, because the mean of its divisors is an integer number (5406435).

Almost surely, 2^21612469 is an apocalyptic number.

It is an amenable number.

21612469 is a deficient number, since it is larger than the sum of its proper divisors (13271).

21612469 is a wasteful number, since it uses less digits than its factorization.

21612469 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13270.

The product of its digits is 5184, while the sum is 31.

The square root of 21612469 is about 4648.9212727255. The cubic root of 21612469 is about 278.5489085705.

The spelling of 21612469 in words is "twenty-one million, six hundred twelve thousand, four hundred sixty-nine".