21557073 has 8 divisors (see below), whose sum is σ = 28888000. Its totient is φ = 14298768.

The previous prime is 21557057. The next prime is 21557099. The reversal of 21557073 is 37075512.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21557073 - 2⁴ = 21557057 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 21557073.

It is not an unprimeable number, because it can be changed into a prime (21557023) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 17458 + ... + 18651.

It is an arithmetic number, because the mean of its divisors is an integer number (3611000).

Almost surely, 2^21557073 is an apocalyptic number.

It is an amenable number.

21557073 is a deficient number, since it is larger than the sum of its proper divisors (7330927).

21557073 is a wasteful number, since it uses less digits than its factorization.

21557073 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 36311.

The product of its (nonzero) digits is 7350, while the sum is 30.

The square root of 21557073 is about 4642.9595087616. The cubic root of 21557073 is about 278.3107174026.

The spelling of 21557073 in words is "twenty-one million, five hundred fifty-seven thousand, seventy-three".