21415199987 has 2 divisors, whose sum is σ = 21415199988. Its totient is φ = 21415199986.

The previous prime is 21415199957. The next prime is 21415200007. The reversal of 21415199987 is 78999151412.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21415199987 - 2¹⁶ = 21415134451 is a prime.

It is a super-2 number, since 2×21415199987² (a number of 21 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21415199917) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10707599993 + 10707599994.

It is an arithmetic number, because the mean of its divisors is an integer number (10707599994).

Almost surely, 2^21415199987 is an apocalyptic number.

21415199987 is a deficient number, since it is larger than the sum of its proper divisors (1).

21415199987 is an equidigital number, since it uses as much as digits as its factorization.

21415199987 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1632960, while the sum is 56.

The spelling of 21415199987 in words is "twenty-one billion, four hundred fifteen million, one hundred ninety-nine thousand, nine hundred eighty-seven".