21382493 has 4 divisors (see below), whose sum is σ = 23326368. Its totient is φ = 19438620.

The previous prime is 21382463. The next prime is 21382499. The reversal of 21382493 is 39428312.

It is a happy number.

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 a cyclic number.

It is not a de Polignac number, because 21382493 - 2¹⁰ = 21381469 is a prime.

It is a super-2 number, since 2×21382493² = 914422013790098, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21382499) 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, 971921 + ... + 971942.

It is an arithmetic number, because the mean of its divisors is an integer number (5831592).

Almost surely, 2^21382493 is an apocalyptic number.

It is an amenable number.

21382493 is a deficient number, since it is larger than the sum of its proper divisors (1943875).

21382493 is a wasteful number, since it uses less digits than its factorization.

21382493 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1943874.

The product of its digits is 10368, while the sum is 32.

The square root of 21382493 is about 4624.1207812945. The cubic root of 21382493 is about 277.5573801210.

The spelling of 21382493 in words is "twenty-one million, three hundred eighty-two thousand, four hundred ninety-three".