21404104051 has 4 divisors (see below), whose sum is σ = 23349931704. Its totient is φ = 19458276400.

The previous prime is 21404104049. The next prime is 21404104081. The reversal of 21404104051 is 15040140412.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21404104051 - 2¹ = 21404104049 is a prime.

It is a super-2 number, since 2×21404104051² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21404104081) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 972913810 + ... + 972913831.

It is an arithmetic number, because the mean of its divisors is an integer number (5837482926).

Almost surely, 2^21404104051 is an apocalyptic number.

21404104051 is a deficient number, since it is larger than the sum of its proper divisors (1945827653).

21404104051 is a wasteful number, since it uses less digits than its factorization.

21404104051 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1945827652.

The product of its (nonzero) digits is 640, while the sum is 22.

Adding to 21404104051 its reverse (15040140412), we get a palindrome (36444244463).

The spelling of 21404104051 in words is "twenty-one billion, four hundred four million, one hundred four thousand, fifty-one".