21040988 has 6 divisors (see below), whose sum is σ = 36821736. Its totient is φ = 10520492.

The previous prime is 21040973. The next prime is 21040997. The reversal of 21040988 is 88904012.

It is a happy number.

It is a super-2 number, since 2×21040988² = 885446352032288, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

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 as a sum of consecutive naturals, namely, 2630120 + ... + 2630127.

It is an arithmetic number, because the mean of its divisors is an integer number (6136956).

Almost surely, 2^21040988 is an apocalyptic number.

It is an amenable number.

21040988 is a deficient number, since it is larger than the sum of its proper divisors (15780748).

21040988 is a wasteful number, since it uses less digits than its factorization.

21040988 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5260251 (or 5260249 counting only the distinct ones).

The product of its (nonzero) digits is 4608, while the sum is 32.

The square root of 21040988 is about 4587.0456723255. The cubic root of 21040988 is about 276.0717974664.

The spelling of 21040988 in words is "twenty-one million, forty thousand, nine hundred eighty-eight".