21554470 has 64 divisors (see below), whose sum is σ = 47900160. Its totient is φ = 6815232.

The previous prime is 21554459. The next prime is 21554471. The reversal of 21554470 is 7445512.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21554471) 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 31 ways as a sum of consecutive naturals, for example, 70057 + ... + 70363.

It is an arithmetic number, because the mean of its divisors is an integer number (748440).

Almost surely, 2^21554470 is an apocalyptic number.

21554470 is an abundant number, since it is smaller than the sum of its proper divisors (26345690).

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

21554470 is a wasteful number, since it uses less digits than its factorization.

21554470 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 397.

The product of its (nonzero) digits is 5600, while the sum is 28.

The square root of 21554470 is about 4642.6791834026. The cubic root of 21554470 is about 278.2995150166.

Adding to 21554470 its reverse (7445512), we get a palindrome (28999982).

The spelling of 21554470 in words is "twenty-one million, five hundred fifty-four thousand, four hundred seventy".