21154533141655 has 4 divisors (see below), whose sum is σ = 25385439769992. Its totient is φ = 16923626513320.

The previous prime is 21154533141617. The next prime is 21154533141671. The reversal of 21154533141655 is 55614133545112.

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

It is not a de Polignac number, because 21154533141655 - 2⁹ = 21154533141143 is a prime.

It is a super-2 number, since 2×21154533141655² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

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, 2115453314161 + ... + 2115453314170.

It is an arithmetic number, because the mean of its divisors is an integer number (6346359942498).

Almost surely, 2^{21154533141655} is an apocalyptic number.

21154533141655 is a deficient number, since it is larger than the sum of its proper divisors (4230906628337).

21154533141655 is an equidigital number, since it uses as much as digits as its factorization.

21154533141655 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4230906628336.

The product of its digits is 1080000, while the sum is 46.

Adding to 21154533141655 its reverse (55614133545112), we get a palindrome (76768666686767).

The spelling of 21154533141655 in words is "twenty-one trillion, one hundred fifty-four billion, five hundred thirty-three million, one hundred forty-one thousand, six hundred fifty-five".