21988773 has 8 divisors (see below), whose sum is σ = 32576000. Its totient is φ = 14659164.

The previous prime is 21988763. The next prime is 21988777. The reversal of 21988773 is 37788912.

It is not a de Polignac number, because 21988773 - 2⁵ = 21988741 is a prime.

It is a super-2 number, since 2×21988773² = 967012276091058, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21988777) 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 7 ways as a sum of consecutive naturals, for example, 407173 + ... + 407226.

It is an arithmetic number, because the mean of its divisors is an integer number (4072000).

Almost surely, 2^21988773 is an apocalyptic number.

It is an amenable number.

21988773 is a deficient number, since it is larger than the sum of its proper divisors (10587227).

21988773 is an equidigital number, since it uses as much as digits as its factorization.

21988773 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 814408 (or 814402 counting only the distinct ones).

The product of its digits is 169344, while the sum is 45.

The square root of 21988773 is about 4689.2188048757. The cubic root of 21988773 is about 280.1562605680.

The spelling of 21988773 in words is "twenty-one million, nine hundred eighty-eight thousand, seven hundred seventy-three".