21100019975 has 12 divisors (see below), whose sum is σ = 26320700784. Its totient is φ = 16778934720.

The previous prime is 21100019971. The next prime is 21100020001. The reversal of 21100019975 is 57991000112.

It is not a de Polignac number, because 21100019975 - 2² = 21100019971 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 (21100019971) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2522774 + ... + 2531123.

It is an arithmetic number, because the mean of its divisors is an integer number (2193391732).

Almost surely, 2^21100019975 is an apocalyptic number.

21100019975 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

21100019975 is a deficient number, since it is larger than the sum of its proper divisors (5220680809).

21100019975 is a wasteful number, since it uses less digits than its factorization.

21100019975 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5054074 (or 5054069 counting only the distinct ones).

The product of its (nonzero) digits is 5670, while the sum is 35.

The spelling of 21100019975 in words is "twenty-one billion, one hundred million, nineteen thousand, nine hundred seventy-five".