21988007 has 8 divisors (see below), whose sum is σ = 22649616. Its totient is φ = 21333312.

The previous prime is 21987989. The next prime is 21988009. The reversal of 21988007 is 70088912.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21988007 - 2¹⁰ = 21986983 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21988009) 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, 5123 + ... + 8379.

It is an arithmetic number, because the mean of its divisors is an integer number (2831202).

Almost surely, 2^21988007 is an apocalyptic number.

21988007 is a deficient number, since it is larger than the sum of its proper divisors (661609).

21988007 is a wasteful number, since it uses less digits than its factorization.

21988007 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3457.

The product of its (nonzero) digits is 8064, while the sum is 35.

The square root of 21988007 is about 4689.1371274468. The cubic root of 21988007 is about 280.1530073596.

The spelling of 21988007 in words is "twenty-one million, nine hundred eighty-eight thousand, seven".