21619387 has 8 divisors (see below), whose sum is σ = 21934880. Its totient is φ = 21306240.

The previous prime is 21619373. The next prime is 21619399. The reversal of 21619387 is 78391612.

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 21619387 - 2¹⁹ = 21095099 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21619357) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 25858 + ... + 26680.

It is an arithmetic number, because the mean of its divisors is an integer number (2741860).

Almost surely, 2^21619387 is an apocalyptic number.

21619387 is a deficient number, since it is larger than the sum of its proper divisors (315493).

21619387 is a wasteful number, since it uses less digits than its factorization.

21619387 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1173.

The product of its digits is 18144, while the sum is 37.

The square root of 21619387 is about 4649.6652567685. The cubic root of 21619387 is about 278.5786259184.

The spelling of 21619387 in words is "twenty-one million, six hundred nineteen thousand, three hundred eighty-seven".