21471213 has 8 divisors (see below), whose sum is σ = 29873088. Its totient is φ = 13691744.

The previous prime is 21471209. The next prime is 21471239. The reversal of 21471213 is 31217412.

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

It is a cyclic number.

It is not a de Polignac number, because 21471213 - 2² = 21471209 is a prime.

It is a super-2 number, since 2×21471213² = 922025975382738, 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 21471213.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21471283) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 155520 + ... + 155657.

It is an arithmetic number, because the mean of its divisors is an integer number (3734136).

Almost surely, 2^21471213 is an apocalyptic number.

21471213 is a gapful number since it is divisible by the number (23) formed by its first and last digit.

It is an amenable number.

21471213 is a deficient number, since it is larger than the sum of its proper divisors (8401875).

21471213 is a wasteful number, since it uses less digits than its factorization.

21471213 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 311203.

The product of its digits is 336, while the sum is 21.

The square root of 21471213 is about 4633.7040259386. The cubic root of 21471213 is about 277.9407297345.

Adding to 21471213 its reverse (31217412), we get a palindrome (52688625).

The spelling of 21471213 in words is "twenty-one million, four hundred seventy-one thousand, two hundred thirteen".