21551634278 has 8 divisors (see below), whose sum is σ = 32462713440. Its totient is φ = 10730729800.

The previous prime is 21551634227. The next prime is 21551634319. The reversal of 21551634278 is 87243615512.

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

It is a congruent number.

It is an unprimeable number.

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 3 ways as a sum of consecutive naturals, for example, 22543073 + ... + 22544028.

It is an arithmetic number, because the mean of its divisors is an integer number (4057839180).

Almost surely, 2^21551634278 is an apocalyptic number.

21551634278 is a deficient number, since it is larger than the sum of its proper divisors (10911079162).

21551634278 is a wasteful number, since it uses less digits than its factorization.

21551634278 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 45087342.

The product of its digits is 403200, while the sum is 44.

The spelling of 21551634278 in words is "twenty-one billion, five hundred fifty-one million, six hundred thirty-four thousand, two hundred seventy-eight".