21048551 has 8 divisors (see below), whose sum is σ = 21391104. Its totient is φ = 20708280.

The previous prime is 21048541. The next prime is 21048553. The reversal of 21048551 is 15584012.

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

It is a cyclic number.

It is not a de Polignac number, because 21048551 - 2⁶ = 21048487 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21048551.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21048553) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 30116 + ... + 30806.

It is an arithmetic number, because the mean of its divisors is an integer number (2673888).

Almost surely, 2^21048551 is an apocalyptic number.

21048551 is a deficient number, since it is larger than the sum of its proper divisors (342553).

21048551 is an equidigital number, since it uses as much as digits as its factorization.

21048551 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1141.

The product of its (nonzero) digits is 1600, while the sum is 26.

The square root of 21048551 is about 4587.8699850802. The cubic root of 21048551 is about 276.1048707056.

The spelling of 21048551 in words is "twenty-one million, forty-eight thousand, five hundred fifty-one".