21935720 has 16 divisors (see below), whose sum is σ = 49355460. Its totient is φ = 8774272.

The previous prime is 21935717. The next prime is 21935723. The reversal of 21935720 is 2753912.

It is an interprime number because it is at equal distance from previous prime (21935717) and next prime (21935723).

It can be written as a sum of positive squares in 2 ways, for example, as 18645124 + 3290596 = 4318^2 + 1814^2 .

It is not an unprimeable number, because it can be changed into a prime (21935723) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 274157 + ... + 274236.

Almost surely, 2^21935720 is an apocalyptic number.

21935720 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21935720 is an abundant number, since it is smaller than the sum of its proper divisors (27419740).

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

21935720 is a wasteful number, since it uses less digits than its factorization.

21935720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 548404 (or 548400 counting only the distinct ones).

The product of its (nonzero) digits is 3780, while the sum is 29.

The square root of 21935720 is about 4683.5584762016. The cubic root of 21935720 is about 279.9307651948.

The spelling of 21935720 in words is "twenty-one million, nine hundred thirty-five thousand, seven hundred twenty".