21458525 has 12 divisors (see below), whose sum is σ = 29027904. Its totient is φ = 15606000.

The previous prime is 21458453. The next prime is 21458527. The reversal of 21458525 is 52585412.

It is not a de Polignac number, because 21458525 - 2¹⁶ = 21392989 is a prime.

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

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21458491 and 21458500.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21458527) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 38741 + ... + 39290.

It is an arithmetic number, because the mean of its divisors is an integer number (2418992).

Almost surely, 2^21458525 is an apocalyptic number.

21458525 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21458525 is a deficient number, since it is larger than the sum of its proper divisors (7569379).

21458525 is a wasteful number, since it uses less digits than its factorization.

21458525 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 78052 (or 78047 counting only the distinct ones).

The product of its digits is 16000, while the sum is 32.

The square root of 21458525 is about 4632.3347245207. The cubic root of 21458525 is about 277.8859710389.

The spelling of 21458525 in words is "twenty-one million, four hundred fifty-eight thousand, five hundred twenty-five".