21695280 has 40 divisors (see below), whose sum is σ = 67256112. Its totient is φ = 5785344.

The previous prime is 21695269. The next prime is 21695291. The reversal of 21695280 is 8259612.

It is an interprime number because it is at equal distance from previous prime (21695269) and next prime (21695291).

It is a tau number, because it is divible by the number of its divisors (40).

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, 44959 + ... + 45438.

Almost surely, 2^21695280 is an apocalyptic number.

21695280 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21695280 is an abundant number, since it is smaller than the sum of its proper divisors (45560832).

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

21695280 is a wasteful number, since it uses less digits than its factorization.

21695280 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 90413 (or 90407 counting only the distinct ones).

The product of its (nonzero) digits is 8640, while the sum is 33.

The square root of 21695280 is about 4657.8192322159. The cubic root of 21695280 is about 278.9042206657.

The spelling of 21695280 in words is "twenty-one million, six hundred ninety-five thousand, two hundred eighty".