21078542199 has 64 divisors (see below), whose sum is σ = 35001566208. Its totient is φ = 11085465600.

The previous prime is 21078542197. The next prime is 21078542227. The reversal of 21078542199 is 99124587012.

It is a happy number.

It is not a de Polignac number, because 21078542199 - 2¹ = 21078542197 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21078542197) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 11821062 + ... + 11822844.

It is an arithmetic number, because the mean of its divisors is an integer number (546899472).

Almost surely, 2^21078542199 is an apocalyptic number.

21078542199 is a deficient number, since it is larger than the sum of its proper divisors (13923024009).

21078542199 is a wasteful number, since it uses less digits than its factorization.

21078542199 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3448.

The product of its (nonzero) digits is 362880, while the sum is 48.

The spelling of 21078542199 in words is "twenty-one billion, seventy-eight million, five hundred forty-two thousand, one hundred ninety-nine".