21919413 has 4 divisors (see below), whose sum is σ = 29225888. Its totient is φ = 14612940.

The previous prime is 21919411. The next prime is 21919427. The reversal of 21919413 is 31491912.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 21919413 - 2¹ = 21919411 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21919411) 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, 3653233 + ... + 3653238.

It is an arithmetic number, because the mean of its divisors is an integer number (7306472).

Almost surely, 2^21919413 is an apocalyptic number.

It is an amenable number.

21919413 is a deficient number, since it is larger than the sum of its proper divisors (7306475).

21919413 is an equidigital number, since it uses as much as digits as its factorization.

21919413 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7306474.

The product of its digits is 1944, while the sum is 30.

The square root of 21919413 is about 4681.8172753750. The cubic root of 21919413 is about 279.8613812157.

The spelling of 21919413 in words is "twenty-one million, nine hundred nineteen thousand, four hundred thirteen".