21540454 has 16 divisors (see below), whose sum is σ = 34875792. Its totient is φ = 9919008.

The previous prime is 21540439. The next prime is 21540473. The reversal of 21540454 is 45404512.

It is a happy number.

It is a super-2 number, since 2×21540454² = 927982317052232, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 17152 + ... + 18364.

It is an arithmetic number, because the mean of its divisors is an integer number (2179737).

Almost surely, 2^21540454 is an apocalyptic number.

21540454 is a deficient number, since it is larger than the sum of its proper divisors (13335338).

21540454 is a wasteful number, since it uses less digits than its factorization.

21540454 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1911.

The product of its (nonzero) digits is 3200, while the sum is 25.

The square root of 21540454 is about 4641.1694646931. The cubic root of 21540454 is about 278.2391796308.

Adding to 21540454 its reverse (45404512), we get a palindrome (66944966).

The spelling of 21540454 in words is "twenty-one million, five hundred forty thousand, four hundred fifty-four".