21016343231247 has 48 divisors (see below), whose sum is σ = 37169175933792. Its totient is φ = 10433452861440.

The previous prime is 21016343231239. The next prime is 21016343231321. The reversal of 21016343231247 is 74213234361012.

It is not a de Polignac number, because 21016343231247 - 2³ = 21016343231239 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (39).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21016343231347) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 323425254 + ... + 323490227.

It is an arithmetic number, because the mean of its divisors is an integer number (774357831954).

Almost surely, 2^{21016343231247} is an apocalyptic number.

21016343231247 is a deficient number, since it is larger than the sum of its proper divisors (16152832702545).

21016343231247 is a wasteful number, since it uses less digits than its factorization.

21016343231247 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 646915528 (or 646915521 counting only the distinct ones).

The product of its (nonzero) digits is 145152, while the sum is 39.

Adding to 21016343231247 its reverse (74213234361012), we get a palindrome (95229577592259).

The spelling of 21016343231247 in words is "twenty-one trillion, sixteen billion, three hundred forty-three million, two hundred thirty-one thousand, two hundred forty-seven".