21988754 has 4 divisors (see below), whose sum is σ = 32983134. Its totient is φ = 10994376.

The previous prime is 21988741. The next prime is 21988763. The reversal of 21988754 is 45788912.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 19669225 + 2319529 = 4435^2 + 1523^2 .

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5497187 + ... + 5497190.

Almost surely, 2^21988754 is an apocalyptic number.

21988754 is a deficient number, since it is larger than the sum of its proper divisors (10994380).

21988754 is a wasteful number, since it uses less digits than its factorization.

21988754 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10994379.

The product of its digits is 161280, while the sum is 44.

The square root of 21988754 is about 4689.2167789515. The cubic root of 21988754 is about 280.1561798758.

The spelling of 21988754 in words is "twenty-one million, nine hundred eighty-eight thousand, seven hundred fifty-four".