21054493 has 8 divisors (see below), whose sum is σ = 21867480. Its totient is φ = 20247360.

The previous prime is 21054457. The next prime is 21054521. The reversal of 21054493 is 39445012.

It can be written as a sum of positive squares in 4 ways, for example, as 3229209 + 17825284 = 1797^2 + 4222^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 21054493 - 2¹³ = 21046301 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 (21054403) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6723 + ... + 9343.

It is an arithmetic number, because the mean of its divisors is an integer number (2733435).

Almost surely, 2^21054493 is an apocalyptic number.

It is an amenable number.

21054493 is a deficient number, since it is larger than the sum of its proper divisors (812987).

21054493 is a wasteful number, since it uses less digits than its factorization.

21054493 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2927.

The product of its (nonzero) digits is 4320, while the sum is 28.

The square root of 21054493 is about 4588.5175165842. The cubic root of 21054493 is about 276.1308497035.

The spelling of 21054493 in words is "twenty-one million, fifty-four thousand, four hundred ninety-three".