21213366011551 has 12 divisors (see below), whose sum is σ = 25753844255728. Its totient is φ = 17113303671552.

The previous prime is 21213366011549. The next prime is 21213366011603. The reversal of 21213366011551 is 15511066331212.

It is not a de Polignac number, because 21213366011551 - 2¹ = 21213366011549 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21213366011551.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21213366041551) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 5243044446 + ... + 5243048491.

Almost surely, 2^{21213366011551} is an apocalyptic number.

21213366011551 is a deficient number, since it is larger than the sum of its proper divisors (4540478244177).

21213366011551 is a wasteful number, since it uses less digits than its factorization.

21213366011551 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10486092978 (or 10486092961 counting only the distinct ones).

The product of its (nonzero) digits is 32400, while the sum is 37.

The spelling of 21213366011551 in words is "twenty-one trillion, two hundred thirteen billion, three hundred sixty-six million, eleven thousand, five hundred fifty-one".