21312219 has 8 divisors (see below), whose sum is σ = 29077312. Its totient is φ = 13877640.

The previous prime is 21312173. The next prime is 21312223. The reversal of 21312219 is 91221312.

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

It is not a de Polignac number, because 21312219 - 2¹³ = 21304027 is a prime.

It is a super-2 number, since 2×21312219² = 908421357407922, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21312195 and 21312204.

It is not an unprimeable number, because it can be changed into a prime (21312229) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 82477 + ... + 82734.

It is an arithmetic number, because the mean of its divisors is an integer number (3634664).

Almost surely, 2^21312219 is an apocalyptic number.

21312219 is a deficient number, since it is larger than the sum of its proper divisors (7765093).

21312219 is a wasteful number, since it uses less digits than its factorization.

21312219 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 165257.

The product of its digits is 216, while the sum is 21.

The square root of 21312219 is about 4616.5158940482. The cubic root of 21312219 is about 277.2529804054.

The spelling of 21312219 in words is "twenty-one million, three hundred twelve thousand, two hundred nineteen".