21216015156511 has 16 divisors (see below), whose sum is σ = 24658066540800. Its totient is φ = 17876767494528.

The previous prime is 21216015156499. The next prime is 21216015156527. The reversal of 21216015156511 is 11565151061212.

It is a cyclic number.

It is not a de Polignac number, because 21216015156511 - 2²³ = 21216006767903 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21216015154511) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 68522896 + ... + 68831818.

It is an arithmetic number, because the mean of its divisors is an integer number (1541129158800).

Almost surely, 2^{21216015156511} is an apocalyptic number.

21216015156511 is a deficient number, since it is larger than the sum of its proper divisors (3442051384289).

21216015156511 is a wasteful number, since it uses less digits than its factorization.

21216015156511 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 475278.

The product of its (nonzero) digits is 18000, while the sum is 37.

The spelling of 21216015156511 in words is "twenty-one trillion, two hundred sixteen billion, fifteen million, one hundred fifty-six thousand, five hundred eleven".