21399445389 has 16 divisors (see below), whose sum is σ = 32615171712. Its totient is φ = 12225819648.

The previous prime is 21399445363. The next prime is 21399445409. The reversal of 21399445389 is 98354499312.

It is not a de Polignac number, because 21399445389 - 2⁵ = 21399445357 is a prime.

It is a super-2 number, since 2×21399445389² (a number of 21 digits) contains 22 as substring.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21399465389) 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, 9337 + ... + 207089.

It is an arithmetic number, because the mean of its divisors is an integer number (2038448232).

Almost surely, 2^21399445389 is an apocalyptic number.

It is an amenable number.

21399445389 is a deficient number, since it is larger than the sum of its proper divisors (11215726323).

21399445389 is a wasteful number, since it uses less digits than its factorization.

21399445389 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 202916.

The product of its digits is 8398080, while the sum is 57.

The spelling of 21399445389 in words is "twenty-one billion, three hundred ninety-nine million, four hundred forty-five thousand, three hundred eighty-nine".