21900006451920 has 40 divisors (see below), whose sum is σ = 67890020001696. Its totient is φ = 5840001720448.

The previous prime is 21900006451909. The next prime is 21900006451933. The reversal of 21900006451920 is 2915460000912.

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

It is a super-2 number, since 2×21900006451920² (a number of 27 digits) contains 22 as substring.

It is a congruent number.

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, 45625013202 + ... + 45625013681.

Almost surely, 2^{21900006451920} is an apocalyptic number.

21900006451920 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21900006451920 is an abundant number, since it is smaller than the sum of its proper divisors (45990013549776).

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

21900006451920 is a wasteful number, since it uses less digits than its factorization.

21900006451920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 91250026899 (or 91250026893 counting only the distinct ones).

The product of its (nonzero) digits is 38880, while the sum is 39.

The spelling of 21900006451920 in words is "twenty-one trillion, nine hundred billion, six million, four hundred fifty-one thousand, nine hundred twenty".