21699220 has 24 divisors (see below), whose sum is σ = 45932544. Its totient is φ = 8610336.

The previous prime is 21699211. The next prime is 21699229. The reversal of 21699220 is 2299612.

It is an interprime number because it is at equal distance from previous prime (21699211) and next prime (21699229).

It is a super-2 number, since 2×21699220² = 941712297216800, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21699229) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1732 + ... + 6811.

It is an arithmetic number, because the mean of its divisors is an integer number (1913856).

Almost surely, 2^21699220 is an apocalyptic number.

21699220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21699220 is an abundant number, since it is smaller than the sum of its proper divisors (24233324).

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

21699220 is a wasteful number, since it uses less digits than its factorization.

21699220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8679 (or 8677 counting only the distinct ones).

The product of its (nonzero) digits is 3888, while the sum is 31.

The square root of 21699220 is about 4658.2421577243. The cubic root of 21699220 is about 278.9211032336.

The spelling of 21699220 in words is "twenty-one million, six hundred ninety-nine thousand, two hundred twenty".