21061939416 has 128 divisors (see below), whose sum is σ = 61641216000. Its totient is φ = 5872758912.

The previous prime is 21061939403. The next prime is 21061939427. The reversal of 21061939416 is 61493916012.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1370125 + ... + 1385411.

It is an arithmetic number, because the mean of its divisors is an integer number (481572000).

Almost surely, 2^21061939416 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21061939416, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30820608000).

21061939416 is an abundant number, since it is smaller than the sum of its proper divisors (40579276584).

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

21061939416 is a wasteful number, since it uses less digits than its factorization.

21061939416 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15501 (or 15497 counting only the distinct ones).

The product of its (nonzero) digits is 69984, while the sum is 42.

The spelling of 21061939416 in words is "twenty-one billion, sixty-one million, nine hundred thirty-nine thousand, four hundred sixteen".