21399155557680 has 40 divisors (see below), whose sum is σ = 66337382229552. Its totient is φ = 5706441481984.

The previous prime is 21399155557609. The next prime is 21399155557691. The reversal of 21399155557680 is 8675555199312.

It is a tau number, because it is divible by the number of its divisors (40).

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 44581573839 + ... + 44581574318.

Almost surely, 2^{21399155557680} is an apocalyptic number.

21399155557680 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21399155557680 is an abundant number, since it is smaller than the sum of its proper divisors (44938226671872).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21399155557680 is a wasteful number, since it uses less digits than its factorization.

21399155557680 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 89163148173 (or 89163148167 counting only the distinct ones).

The product of its (nonzero) digits is 102060000, while the sum is 66.

The spelling of 21399155557680 in words is "twenty-one trillion, three hundred ninety-nine billion, one hundred fifty-five million, five hundred fifty-seven thousand, six hundred eighty".