21799560 has 64 divisors (see below), whose sum is σ = 65707200. Its totient is φ = 5785856.

The previous prime is 21799553. The next prime is 21799567. The reversal of 21799560 is 6599712.

It is a Cunningham number, because it is equal to 4669²-1.

It is an interprime number because it is at equal distance from previous prime (21799553) and next prime (21799567).

It is not an unprimeable number, because it can be changed into a prime (21799567) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 46447 + ... + 46913.

It is an arithmetic number, because the mean of its divisors is an integer number (1026675).

Almost surely, 2^21799560 is an apocalyptic number.

21799560 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21799560 is an abundant number, since it is smaller than the sum of its proper divisors (43907640).

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

21799560 is a wasteful number, since it uses less digits than its factorization.

21799560 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 870 (or 866 counting only the distinct ones).

The product of its (nonzero) digits is 34020, while the sum is 39.

The square root of 21799560 is about 4668.9998929107. Note that the first 3 decimals coincide. The cubic root of 21799560 is about 279.3503646781.

The spelling of 21799560 in words is "twenty-one million, seven hundred ninety-nine thousand, five hundred sixty".