21099739867 has 2 divisors, whose sum is σ = 21099739868. Its totient is φ = 21099739866.

The previous prime is 21099739853. The next prime is 21099739877. The reversal of 21099739867 is 76893799012.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21099739867 - 2¹⁵ = 21099707099 is a prime.

It is not a weakly prime, because it can be changed into another prime (21099739877) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10549869933 + 10549869934.

It is an arithmetic number, because the mean of its divisors is an integer number (10549869934).

Almost surely, 2^21099739867 is an apocalyptic number.

21099739867 is a deficient number, since it is larger than the sum of its proper divisors (1).

21099739867 is an equidigital number, since it uses as much as digits as its factorization.

21099739867 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 10287648, while the sum is 61.

The spelling of 21099739867 in words is "twenty-one billion, ninety-nine million, seven hundred thirty-nine thousand, eight hundred sixty-seven".