21451850 has 24 divisors (see below), whose sum is σ = 45601248. Its totient is φ = 7354800.

The previous prime is 21451849. The next prime is 21451861. The reversal of 21451850 is 5815412.

It is a Curzon number.

It is an unprimeable number.

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 11 ways as a sum of consecutive naturals, for example, 30296 + ... + 30995.

It is an arithmetic number, because the mean of its divisors is an integer number (1900052).

Almost surely, 2^21451850 is an apocalyptic number.

21451850 is an abundant number, since it is smaller than the sum of its proper divisors (24149398).

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

21451850 is a wasteful number, since it uses less digits than its factorization.

21451850 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 61310 (or 61305 counting only the distinct ones).

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

The square root of 21451850 is about 4631.6141894592. The cubic root of 21451850 is about 277.8571545006.

The spelling of 21451850 in words is "twenty-one million, four hundred fifty-one thousand, eight hundred fifty".