21554525 has 6 divisors (see below), whose sum is σ = 26727642. Its totient is φ = 17243600.

The previous prime is 21554513. The next prime is 21554537. The reversal of 21554525 is 52545512.

It is an interprime number because it is at equal distance from previous prime (21554513) and next prime (21554537).

It can be written as a sum of positive squares in 3 ways, for example, as 1582564 + 19971961 = 1258^2 + 4469^2 .

It is not a de Polignac number, because 21554525 - 2⁴ = 21554509 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 431066 + ... + 431115.

It is an arithmetic number, because the mean of its divisors is an integer number (4454607).

Almost surely, 2^21554525 is an apocalyptic number.

21554525 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21554525 is a deficient number, since it is larger than the sum of its proper divisors (5173117).

21554525 is an equidigital number, since it uses as much as digits as its factorization.

21554525 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 862191 (or 862186 counting only the distinct ones).

The product of its digits is 10000, while the sum is 29.

The square root of 21554525 is about 4642.6851067028. The cubic root of 21554525 is about 278.2997517263.

The spelling of 21554525 in words is "twenty-one million, five hundred fifty-four thousand, five hundred twenty-five".