21554025 has 12 divisors (see below), whose sum is σ = 35636112. Its totient is φ = 11495440.

The previous prime is 21553997. The next prime is 21554033. The reversal of 21554025 is 52045512.

It is a happy number.

It is not a de Polignac number, because 21554025 - 2¹³ = 21545833 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21553986 and 21554004.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 143619 + ... + 143768.

It is an arithmetic number, because the mean of its divisors is an integer number (2969676).

Almost surely, 2^21554025 is an apocalyptic number.

21554025 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21554025 is a deficient number, since it is larger than the sum of its proper divisors (14082087).

21554025 is a wasteful number, since it uses less digits than its factorization.

21554025 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 287400 (or 287395 counting only the distinct ones).

The product of its (nonzero) digits is 2000, while the sum is 24.

The square root of 21554025 is about 4642.6312582414. The cubic root of 21554025 is about 278.2975998046.

Adding to 21554025 its reverse (52045512), we get a palindrome (73599537).

The spelling of 21554025 in words is "twenty-one million, five hundred fifty-four thousand, twenty-five".