21878406869 has 8 divisors (see below), whose sum is σ = 23972498208. Its totient is φ = 19801839760.

The previous prime is 21878406859. The next prime is 21878406877. The reversal of 21878406869 is 96860487812.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21878406869 is a prime.

It is a super-2 number, since 2×21878406869² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21878406859) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4378442 + ... + 4383435.

It is an arithmetic number, because the mean of its divisors is an integer number (2996562276).

Almost surely, 2^21878406869 is an apocalyptic number.

It is an amenable number.

21878406869 is a deficient number, since it is larger than the sum of its proper divisors (2094091339).

21878406869 is a wasteful number, since it uses less digits than its factorization.

21878406869 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8762115.

The product of its (nonzero) digits is 9289728, while the sum is 59.

The spelling of 21878406869 in words is "twenty-one billion, eight hundred seventy-eight million, four hundred six thousand, eight hundred sixty-nine".