21552851 has 2 divisors, whose sum is σ = 21552852. Its totient is φ = 21552850.

The previous prime is 21552841. The next prime is 21552893. The reversal of 21552851 is 15825512.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21552851 is a prime.

It is not a weakly prime, because it can be changed into another prime (21552841) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10776425 + 10776426.

It is an arithmetic number, because the mean of its divisors is an integer number (10776426).

Almost surely, 2^21552851 is an apocalyptic number.

21552851 is a deficient number, since it is larger than the sum of its proper divisors (1).

21552851 is an equidigital number, since it uses as much as digits as its factorization.

21552851 is an evil number, because the sum of its binary digits is even.

The product of its digits is 4000, while the sum is 29.

The square root of 21552851 is about 4642.5048195990. The cubic root of 21552851 is about 278.2925469616.

The spelling of 21552851 in words is "twenty-one million, five hundred fifty-two thousand, eight hundred fifty-one".