21438707521155 has 16 divisors (see below), whose sum is σ = 34532146346400. Its totient is φ = 11357239240448.

The previous prime is 21438707521111. The next prime is 21438707521169. The reversal of 21438707521155 is 55112570783412.

It is a cyclic number.

It is not a de Polignac number, because 21438707521155 - 2⁷ = 21438707521027 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21438707521098 and 21438707521107.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4796129202 + ... + 4796133671.

It is an arithmetic number, because the mean of its divisors is an integer number (2158259146650).

Almost surely, 2^{21438707521155} is an apocalyptic number.

21438707521155 is a deficient number, since it is larger than the sum of its proper divisors (13093438825245).

21438707521155 is a wasteful number, since it uses less digits than its factorization.

21438707521155 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9592263030.

The product of its (nonzero) digits is 2352000, while the sum is 51.

The spelling of 21438707521155 in words is "twenty-one trillion, four hundred thirty-eight billion, seven hundred seven million, five hundred twenty-one thousand, one hundred fifty-five".