21073899 has 16 divisors (see below), whose sum is σ = 35032320. Its totient is φ = 10947360.

The previous prime is 21073891. The next prime is 21073909. The reversal of 21073899 is 99837012.

It is not a de Polignac number, because 21073899 - 2³ = 21073891 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21073891) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 45384 + ... + 45845.

It is an arithmetic number, because the mean of its divisors is an integer number (2189520).

Almost surely, 2^21073899 is an apocalyptic number.

21073899 is a deficient number, since it is larger than the sum of its proper divisors (13958421).

21073899 is a wasteful number, since it uses less digits than its factorization.

21073899 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 91250.

The product of its (nonzero) digits is 27216, while the sum is 39.

The square root of 21073899 is about 4590.6316558835. The cubic root of 21073899 is about 276.2156605760.

It can be divided in two parts, 2107 and 3899, that added together give a palindrome (6006).

The spelling of 21073899 in words is "twenty-one million, seventy-three thousand, eight hundred ninety-nine".