21860493 has 4 divisors (see below), whose sum is σ = 29147328. Its totient is φ = 14573660.

The previous prime is 21860483. The next prime is 21860497. The reversal of 21860493 is 39406812.

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 21860493 - 2⁴ = 21860477 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21860497) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3643413 + ... + 3643418.

It is an arithmetic number, because the mean of its divisors is an integer number (7286832).

Almost surely, 2^21860493 is an apocalyptic number.

It is an amenable number.

21860493 is a deficient number, since it is larger than the sum of its proper divisors (7286835).

21860493 is an equidigital number, since it uses as much as digits as its factorization.

21860493 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7286834.

The product of its (nonzero) digits is 10368, while the sum is 33.

The square root of 21860493 is about 4675.5206127233. The cubic root of 21860493 is about 279.6103977705.

The spelling of 21860493 in words is "twenty-one million, eight hundred sixty thousand, four hundred ninety-three".