21902699891 has 2 divisors, whose sum is σ = 21902699892. Its totient is φ = 21902699890.

The previous prime is 21902699879. The next prime is 21902699899. The reversal of 21902699891 is 19899620912.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21902699891 - 2¹⁴ = 21902683507 is a prime.

It is a super-2 number, since 2×21902699891² (a number of 21 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21902699899) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10951349945 + 10951349946.

It is an arithmetic number, because the mean of its divisors is an integer number (10951349946).

Almost surely, 2^21902699891 is an apocalyptic number.

21902699891 is a deficient number, since it is larger than the sum of its proper divisors (1).

21902699891 is an equidigital number, since it uses as much as digits as its factorization.

21902699891 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1259712, while the sum is 56.

The spelling of 21902699891 in words is "twenty-one billion, nine hundred two million, six hundred ninety-nine thousand, eight hundred ninety-one".