27969921 has 32 divisors (see below), whose sum is σ = 47953920. Its totient is φ = 15781392.

The previous prime is 27969917. The next prime is 27969923. The reversal of 27969921 is 12996972.

It is not a de Polignac number, because 27969921 - 2² = 27969917 is a prime.

It is not an unprimeable number, because it can be changed into a prime (27969923) by changing a digit.

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 31 ways as a sum of consecutive naturals, for example, 14796 + ... + 16578.

It is an arithmetic number, because the mean of its divisors is an integer number (1498560).

Almost surely, 2^27969921 is an apocalyptic number.

27969921 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

27969921 is a deficient number, since it is larger than the sum of its proper divisors (19983999).

27969921 is a wasteful number, since it uses less digits than its factorization.

27969921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1882 (or 1876 counting only the distinct ones).

The product of its digits is 122472, while the sum is 45.

The square root of 27969921 is about 5288.6596600651. The cubic root of 27969921 is about 303.5501230380.

The spelling of 27969921 in words is "twenty-seven million, nine hundred sixty-nine thousand, nine hundred twenty-one".