21054015 has 12 divisors (see below), whose sum is σ = 36493704. Its totient is φ = 11228784.

The previous prime is 21053987. The next prime is 21054017. The reversal of 21054015 is 51045012.

It is not a de Polignac number, because 21054015 - 2⁵ = 21053983 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21054017) 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 11 ways as a sum of consecutive naturals, for example, 233889 + ... + 233978.

It is an arithmetic number, because the mean of its divisors is an integer number (3041142).

Almost surely, 2^21054015 is an apocalyptic number.

21054015 is a deficient number, since it is larger than the sum of its proper divisors (15439689).

21054015 is a wasteful number, since it uses less digits than its factorization.

21054015 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 467878 (or 467875 counting only the distinct ones).

The product of its (nonzero) digits is 200, while the sum is 18.

The square root of 21054015 is about 4588.4654297488. The cubic root of 21054015 is about 276.1287600221.

Adding to 21054015 its reverse (51045012), we get a palindrome (72099027).

The spelling of 21054015 in words is "twenty-one million, fifty-four thousand, fifteen".