21878872797 has 16 divisors (see below), whose sum is σ = 30500023680. Its totient is φ = 13924312512.

The previous prime is 21878872793. The next prime is 21878872801. The reversal of 21878872797 is 79727887812.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (21878872793) and next prime (21878872801).

It is not a de Polignac number, because 21878872797 - 2² = 21878872793 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21878872793) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 276358 + ... + 346599.

It is an arithmetic number, because the mean of its divisors is an integer number (1906251480).

Almost surely, 2^21878872797 is an apocalyptic number.

It is an amenable number.

21878872797 is a deficient number, since it is larger than the sum of its proper divisors (8621150883).

21878872797 is a wasteful number, since it uses less digits than its factorization.

21878872797 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 623492.

The product of its digits is 44255232, while the sum is 66.

The spelling of 21878872797 in words is "twenty-one billion, eight hundred seventy-eight million, eight hundred seventy-two thousand, seven hundred ninety-seven".