21746145997 has 4 divisors (see below), whose sum is σ = 22008147840. Its totient is φ = 21484144156.

The previous prime is 21746145977. The next prime is 21746146001. The reversal of 21746145997 is 79954164712.

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 a de Polignac number, because none of the positive numbers 2^k-21746145997 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21746145907) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 131000797 + ... + 131000962.

It is an arithmetic number, because the mean of its divisors is an integer number (5502036960).

Almost surely, 2^21746145997 is an apocalyptic number.

It is an amenable number.

21746145997 is a deficient number, since it is larger than the sum of its proper divisors (262001843).

21746145997 is an equidigital number, since it uses as much as digits as its factorization.

21746145997 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 262001842.

The product of its digits is 3810240, while the sum is 55.

The spelling of 21746145997 in words is "twenty-one billion, seven hundred forty-six million, one hundred forty-five thousand, nine hundred ninety-seven".