21017869628 has 24 divisors (see below), whose sum is σ = 42421394400. Its totient is φ = 8925018048.

The previous prime is 21017869553. The next prime is 21017869633. The reversal of 21017869628 is 82696871012.

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, 3440243 + ... + 3446346.

It is an arithmetic number, because the mean of its divisors is an integer number (1767558100).

Almost surely, 2^21017869628 is an apocalyptic number.

21017869628 is a gapful number since it is divisible by the number (28) formed by its first and last digit.

It is an amenable number.

21017869628 is an abundant number, since it is smaller than the sum of its proper divisors (21403524772).

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

21017869628 is a wasteful number, since it uses less digits than its factorization.

21017869628 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6886709 (or 6886707 counting only the distinct ones).

The product of its (nonzero) digits is 580608, while the sum is 50.

The spelling of 21017869628 in words is "twenty-one billion, seventeen million, eight hundred sixty-nine thousand, six hundred twenty-eight".