21757231361 has 4 divisors (see below), whose sum is σ = 21890711472. Its totient is φ = 21623751252.

The previous prime is 21757231357. The next prime is 21757231381. The reversal of 21757231361 is 16313275712.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21757231361 - 2² = 21757231357 is a prime.

It is a super-3 number, since 3×21757231361³ (a number of 32 digits) contains 333 as substring.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21757231381) 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, 66739811 + ... + 66740136.

It is an arithmetic number, because the mean of its divisors is an integer number (5472677868).

Almost surely, 2^21757231361 is an apocalyptic number.

It is an amenable number.

21757231361 is a deficient number, since it is larger than the sum of its proper divisors (133480111).

21757231361 is a wasteful number, since it uses less digits than its factorization.

21757231361 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 133480110.

The product of its digits is 52920, while the sum is 38.

The spelling of 21757231361 in words is "twenty-one billion, seven hundred fifty-seven million, two hundred thirty-one thousand, three hundred sixty-one".