21040121610 has 48 divisors (see below), whose sum is σ = 55103650056. Its totient is φ = 5569741824.

The previous prime is 21040121593. The next prime is 21040121633. The reversal of 21040121610 is 1612104012.

21040121610 is a `hidden beast` number, since 2 + 1 + 0 + 40 + 12 + 1 + 610 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 19137678921 + 1902442689 = 138339^2 + 43617^2 .

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 840879 + ... + 865538.

Almost surely, 2^21040121610 is an apocalyptic number.

21040121610 is an abundant number, since it is smaller than the sum of its proper divisors (34063528446).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21040121610 is a wasteful number, since it uses less digits than its factorization.

21040121610 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1706567 (or 1706564 counting only the distinct ones).

The product of its (nonzero) digits is 96, while the sum is 18.

Adding to 21040121610 its reverse (1612104012), we get a palindrome (22652225622).

The spelling of 21040121610 in words is "twenty-one billion, forty million, one hundred twenty-one thousand, six hundred ten".