21762419821 has 2 divisors, whose sum is σ = 21762419822. Its totient is φ = 21762419820.

The previous prime is 21762419779. The next prime is 21762419837. The reversal of 21762419821 is 12891426712.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18710409796 + 3052010025 = 136786^2 + 55245^2 .

It is a cyclic number.

It is not a de Polignac number, because 21762419821 - 2¹⁷ = 21762288749 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21762419891) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10881209910 + 10881209911.

It is an arithmetic number, because the mean of its divisors is an integer number (10881209911).

Almost surely, 2^21762419821 is an apocalyptic number.

It is an amenable number.

21762419821 is a deficient number, since it is larger than the sum of its proper divisors (1).

21762419821 is an equidigital number, since it uses as much as digits as its factorization.

21762419821 is an evil number, because the sum of its binary digits is even.

The product of its digits is 96768, while the sum is 43.

The spelling of 21762419821 in words is "twenty-one billion, seven hundred sixty-two million, four hundred nineteen thousand, eight hundred twenty-one".