20421938780 has 12 divisors (see below), whose sum is σ = 42886071480. Its totient is φ = 8168775504.

The previous prime is 20421938759. The next prime is 20421938783. The reversal of 20421938780 is 8783912402.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20421938783) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 510548450 + ... + 510548489.

It is an arithmetic number, because the mean of its divisors is an integer number (3573839290).

Almost surely, 2^20421938780 is an apocalyptic number.

20421938780 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20421938780 is an abundant number, since it is smaller than the sum of its proper divisors (22464132700).

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

20421938780 is a wasteful number, since it uses less digits than its factorization.

20421938780 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1021096948 (or 1021096946 counting only the distinct ones).

The product of its (nonzero) digits is 193536, while the sum is 44.

The spelling of 20421938780 in words is "twenty billion, four hundred twenty-one million, nine hundred thirty-eight thousand, seven hundred eighty".