20958400987 has 2 divisors, whose sum is σ = 20958400988. Its totient is φ = 20958400986.

The previous prime is 20958400979. The next prime is 20958400993. The reversal of 20958400987 is 78900485902.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 20958400987 - 2³ = 20958400979 is a prime.

It is not a weakly prime, because it can be changed into another prime (20958400087) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10479200493 + 10479200494.

It is an arithmetic number, because the mean of its divisors is an integer number (10479200494).

Almost surely, 2^20958400987 is an apocalyptic number.

20958400987 is a deficient number, since it is larger than the sum of its proper divisors (1).

20958400987 is an equidigital number, since it uses as much as digits as its factorization.

20958400987 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1451520, while the sum is 52.

The spelling of 20958400987 in words is "twenty billion, nine hundred fifty-eight million, four hundred thousand, nine hundred eighty-seven".