21357178347 has 16 divisors (see below), whose sum is σ = 29399454720. Its totient is φ = 13776655200.

The previous prime is 21357178313. The next prime is 21357178357. The reversal of 21357178347 is 74387175312.

It is not a de Polignac number, because 21357178347 - 2¹⁴ = 21357161963 is a prime.

It is a super-2 number, since 2×21357178347² (a number of 21 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21357178296 and 21357178305.

It is not an unprimeable number, because it can be changed into a prime (21357178357) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 750397 + ... + 778337.

It is an arithmetic number, because the mean of its divisors is an integer number (1837465920).

Almost surely, 2^21357178347 is an apocalyptic number.

21357178347 is a deficient number, since it is larger than the sum of its proper divisors (8042276373).

21357178347 is a wasteful number, since it uses less digits than its factorization.

21357178347 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 36194.

The product of its digits is 987840, while the sum is 48.

The spelling of 21357178347 in words is "twenty-one billion, three hundred fifty-seven million, one hundred seventy-eight thousand, three hundred forty-seven".