21354551255215 has 16 divisors (see below), whose sum is σ = 25632176226048. Its totient is φ = 17079165156096.

The previous prime is 21354551255171. The next prime is 21354551255293. The reversal of 21354551255215 is 51255215545312.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 21354551255215 - 2⁹ = 21354551254703 is a prime.

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 15 ways as a sum of consecutive naturals, for example, 344136322 + ... + 344198368.

It is an arithmetic number, because the mean of its divisors is an integer number (1602011014128).

Almost surely, 2^{21354551255215} is an apocalyptic number.

21354551255215 is a deficient number, since it is larger than the sum of its proper divisors (4277624970833).

21354551255215 is a wasteful number, since it uses less digits than its factorization.

21354551255215 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 78978.

The product of its digits is 1500000, while the sum is 46.

The spelling of 21354551255215 in words is "twenty-one trillion, three hundred fifty-four billion, five hundred fifty-one million, two hundred fifty-five thousand, two hundred fifteen".