21501889 has 12 divisors (see below), whose sum is σ = 23341824. Its totient is φ = 19793984.

The previous prime is 21501869. The next prime is 21501899. The reversal of 21501889 is 98810512.

It is not a de Polignac number, because 21501889 - 2⁹ = 21501377 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21501859) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 12792 + ... + 14374.

It is an arithmetic number, because the mean of its divisors is an integer number (1945152).

Almost surely, 2^21501889 is an apocalyptic number.

It is an amenable number.

21501889 is a deficient number, since it is larger than the sum of its proper divisors (1839935).

21501889 is a wasteful number, since it uses less digits than its factorization.

21501889 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1664 (or 1647 counting only the distinct ones).

The product of its (nonzero) digits is 5760, while the sum is 34.

The square root of 21501889 is about 4637.0129393824. The cubic root of 21501889 is about 278.0730317244.

The spelling of 21501889 in words is "twenty-one million, five hundred one thousand, eight hundred eighty-nine".