21357177329 has 4 divisors (see below), whose sum is σ = 21649741476. Its totient is φ = 21064613184.

The previous prime is 21357177253. The next prime is 21357177341. The reversal of 21357177329 is 92377175312.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 12199644304 + 9157533025 = 110452^2 + 95695^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21357177329 is a prime.

It is a super-2 number, since 2×21357177329² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21357173329) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 146281964 + ... + 146282109.

It is an arithmetic number, because the mean of its divisors is an integer number (5412435369).

Almost surely, 2^21357177329 is an apocalyptic number.

It is an amenable number.

21357177329 is a deficient number, since it is larger than the sum of its proper divisors (292564147).

21357177329 is an equidigital number, since it uses as much as digits as its factorization.

21357177329 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 292564146.

The product of its digits is 555660, while the sum is 47.

The spelling of 21357177329 in words is "twenty-one billion, three hundred fifty-seven million, one hundred seventy-seven thousand, three hundred twenty-nine".