20674197721 has 2 divisors, whose sum is σ = 20674197722. Its totient is φ = 20674197720.

The previous prime is 20674197689. The next prime is 20674197757. The reversal of 20674197721 is 12779147602.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 16450627600 + 4223570121 = 128260^2 + 64989^2 .

It is a cyclic number.

It is not a de Polignac number, because 20674197721 - 2⁵ = 20674197689 is a prime.

It is not a weakly prime, because it can be changed into another prime (20674197781) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10337098860 + 10337098861.

It is an arithmetic number, because the mean of its divisors is an integer number (10337098861).

Almost surely, 2^20674197721 is an apocalyptic number.

It is an amenable number.

20674197721 is a deficient number, since it is larger than the sum of its proper divisors (1).

20674197721 is an equidigital number, since it uses as much as digits as its factorization.

20674197721 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 296352, while the sum is 46.

The spelling of 20674197721 in words is "twenty billion, six hundred seventy-four million, one hundred ninety-seven thousand, seven hundred twenty-one".