21000401144 has 16 divisors (see below), whose sum is σ = 39915147120. Its totient is φ = 10356361920.

The previous prime is 21000401129. The next prime is 21000401153. The reversal of 21000401144 is 44110400012.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 17979212 + ... + 17980379.

It is an arithmetic number, because the mean of its divisors is an integer number (2494696695).

Almost surely, 2^21000401144 is an apocalyptic number.

It is an amenable number.

21000401144 is a deficient number, since it is larger than the sum of its proper divisors (18914745976).

21000401144 is a wasteful number, since it uses less digits than its factorization.

21000401144 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 35959670 (or 35959666 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 17.

Adding to 21000401144 its reverse (44110400012), we get a palindrome (65110801156).

The spelling of 21000401144 in words is "twenty-one billion, four hundred one thousand, one hundred forty-four".