21054145 has 16 divisors (see below), whose sum is σ = 29871360. Its totient is φ = 13938624.

The previous prime is 21054119. The next prime is 21054169. The reversal of 21054145 is 54145012.

It is not a de Polignac number, because 21054145 - 2⁷ = 21054017 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 9357 + ... + 11386.

It is an arithmetic number, because the mean of its divisors is an integer number (1866960).

Almost surely, 2^21054145 is an apocalyptic number.

It is an amenable number.

21054145 is a deficient number, since it is larger than the sum of its proper divisors (8817215).

21054145 is a wasteful number, since it uses less digits than its factorization.

21054145 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20784.

The product of its (nonzero) digits is 800, while the sum is 22.

The square root of 21054145 is about 4588.4795956831. The cubic root of 21054145 is about 276.1293283486.

Adding to 21054145 its reverse (54145012), we get a palindrome (75199157).

The spelling of 21054145 in words is "twenty-one million, fifty-four thousand, one hundred forty-five".