21207798 has 16 divisors (see below), whose sum is σ = 47128560. Its totient is φ = 7069248.

The previous prime is 21207793. The next prime is 21207811. The reversal of 21207798 is 89770212.

It is a hoax number, since the sum of its digits (36) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21207793) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 196315 + ... + 196422.

It is an arithmetic number, because the mean of its divisors is an integer number (2945535).

Almost surely, 2^21207798 is an apocalyptic number.

21207798 is an abundant number, since it is smaller than the sum of its proper divisors (25920762).

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

21207798 is a wasteful number, since it uses less digits than its factorization.

21207798 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 392748 (or 392742 counting only the distinct ones).

The product of its (nonzero) digits is 14112, while the sum is 36.

The square root of 21207798 is about 4605.1925041197. The cubic root of 21207798 is about 276.7994308045.

The spelling of 21207798 in words is "twenty-one million, two hundred seven thousand, seven hundred ninety-eight".