21530454 has 16 divisors (see below), whose sum is σ = 46975680. Its totient is φ = 6524360.

The previous prime is 21530447. The next prime is 21530459. The reversal of 21530454 is 45403512.

It is a super-2 number, since 2×21530454² = 927120898892232, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21530459) 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 7 ways as a sum of consecutive naturals, for example, 163044 + ... + 163175.

It is an arithmetic number, because the mean of its divisors is an integer number (2935980).

Almost surely, 2^21530454 is an apocalyptic number.

21530454 is an abundant number, since it is smaller than the sum of its proper divisors (25445226).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21530454 is a wasteful number, since it uses less digits than its factorization.

21530454 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 326235.

The product of its (nonzero) digits is 2400, while the sum is 24.

The square root of 21530454 is about 4640.0920249495. The cubic root of 21530454 is about 278.1961161238.

Adding to 21530454 its reverse (45403512), we get a palindrome (66933966).

The spelling of 21530454 in words is "twenty-one million, five hundred thirty thousand, four hundred fifty-four".