21898965 has 16 divisors (see below), whose sum is σ = 38223936. Its totient is φ = 10617600.

The previous prime is 21898951. The next prime is 21898993. The reversal of 21898965 is 56989812.

It is a happy number.

It is not a de Polignac number, because 21898965 - 2⁶ = 21898901 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 66196 + ... + 66525.

It is an arithmetic number, because the mean of its divisors is an integer number (2388996).

Almost surely, 2^21898965 is an apocalyptic number.

It is an amenable number.

21898965 is a deficient number, since it is larger than the sum of its proper divisors (16324971).

21898965 is a wasteful number, since it uses less digits than its factorization.

21898965 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 132740.

The product of its digits is 311040, while the sum is 48.

The square root of 21898965 is about 4679.6329984305. The cubic root of 21898965 is about 279.7743292201.

The spelling of 21898965 in words is "twenty-one million, eight hundred ninety-eight thousand, nine hundred sixty-five".