21860053 has 4 divisors (see below), whose sum is σ = 22565248. Its totient is φ = 21154860.

The previous prime is 21859987. The next prime is 21860057. The reversal of 21860053 is 35006812.

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 21860053 - 2¹⁷ = 21728981 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 (21860057) 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, 352551 + ... + 352612.

It is an arithmetic number, because the mean of its divisors is an integer number (5641312).

Almost surely, 2^21860053 is an apocalyptic number.

It is an amenable number.

21860053 is a deficient number, since it is larger than the sum of its proper divisors (705195).

21860053 is an equidigital number, since it uses as much as digits as its factorization.

21860053 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 705194.

The product of its (nonzero) digits is 1440, while the sum is 25.

The square root of 21860053 is about 4675.4735589029. The cubic root of 21860053 is about 279.6085217927.

Adding to 21860053 its reverse (35006812), we get a palindrome (56866865).

The spelling of 21860053 in words is "twenty-one million, eight hundred sixty thousand, fifty-three".