21477889 has 2 divisors, whose sum is σ = 21477890. Its totient is φ = 21477888.

The previous prime is 21477877. The next prime is 21477913. The reversal of 21477889 is 98877412.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 13542400 + 7935489 = 3680^2 + 2817^2 .

It is a cyclic number.

It is not a de Polignac number, because 21477889 - 2¹⁵ = 21445121 is a prime.

It is a super-2 number, since 2×21477889² = 922599431792642, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21477089) 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 as a sum of consecutive naturals, namely, 10738944 + 10738945.

It is an arithmetic number, because the mean of its divisors is an integer number (10738945).

Almost surely, 2^21477889 is an apocalyptic number.

It is an amenable number.

21477889 is a deficient number, since it is larger than the sum of its proper divisors (1).

21477889 is an equidigital number, since it uses as much as digits as its factorization.

21477889 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 225792, while the sum is 46.

The square root of 21477889 is about 4634.4243439720. The cubic root of 21477889 is about 277.9695332621.

It can be divided in two parts, 21477 and 889, that added together give a triangular number (22366 = T₂₁₁).

The spelling of 21477889 in words is "twenty-one million, four hundred seventy-seven thousand, eight hundred eighty-nine".