21002098987 has 2 divisors, whose sum is σ = 21002098988. Its totient is φ = 21002098986.

The previous prime is 21002098973. The next prime is 21002098991. The reversal of 21002098987 is 78989020012.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21002098987 is a prime.

It is not a weakly prime, because it can be changed into another prime (21002098937) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10501049493 + 10501049494.

It is an arithmetic number, because the mean of its divisors is an integer number (10501049494).

Almost surely, 2^21002098987 is an apocalyptic number.

21002098987 is a deficient number, since it is larger than the sum of its proper divisors (1).

21002098987 is an equidigital number, since it uses as much as digits as its factorization.

21002098987 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 145152, while the sum is 46.

The spelling of 21002098987 in words is "twenty-one billion, two million, ninety-eight thousand, nine hundred eighty-seven".