21000420999 has 6 divisors (see below), whose sum is σ = 30333941456. Its totient is φ = 14000280660.

The previous prime is 21000420983. The next prime is 21000421003. The reversal of 21000420999 is 99902400012.

It is not a de Polignac number, because 21000420999 - 2⁴ = 21000420983 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21000420919) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1166690047 + ... + 1166690064.

Almost surely, 2^21000420999 is an apocalyptic number.

21000420999 is a deficient number, since it is larger than the sum of its proper divisors (9333520457).

21000420999 is a wasteful number, since it uses less digits than its factorization.

21000420999 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2333380117 (or 2333380114 counting only the distinct ones).

The product of its (nonzero) digits is 11664, while the sum is 36.

The spelling of 21000420999 in words is "twenty-one billion, four hundred twenty thousand, nine hundred ninety-nine".