21053518 has 8 divisors (see below), whose sum is σ = 32433912. Its totient is φ = 10242216.

The previous prime is 21053503. The next prime is 21053521. The reversal of 21053518 is 81535012.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a junction number, because it is equal to n+sod(n) for n = 21053492 and 21053501.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 142180 + ... + 142327.

It is an arithmetic number, because the mean of its divisors is an integer number (4054239).

Almost surely, 2^21053518 is an apocalyptic number.

21053518 is a deficient number, since it is larger than the sum of its proper divisors (11380394).

21053518 is a wasteful number, since it uses less digits than its factorization.

21053518 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 284546.

The product of its (nonzero) digits is 1200, while the sum is 25.

The square root of 21053518 is about 4588.4112718892. The cubic root of 21053518 is about 276.1265872446.

The spelling of 21053518 in words is "twenty-one million, fifty-three thousand, five hundred eighteen".