21921477 has 8 divisors (see below), whose sum is σ = 30236640. Its totient is φ = 14110320.

The previous prime is 21921469. The next prime is 21921481. The reversal of 21921477 is 77412912.

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

It is not a de Polignac number, because 21921477 - 2³ = 21921469 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21921407) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 125899 + ... + 126072.

It is an arithmetic number, because the mean of its divisors is an integer number (3779580).

Almost surely, 2^21921477 is an apocalyptic number.

It is an amenable number.

21921477 is a deficient number, since it is larger than the sum of its proper divisors (8315163).

21921477 is a wasteful number, since it uses less digits than its factorization.

21921477 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 252003.

The product of its digits is 7056, while the sum is 33.

The square root of 21921477 is about 4682.0376974134. The cubic root of 21921477 is about 279.8701651456.

The spelling of 21921477 in words is "twenty-one million, nine hundred twenty-one thousand, four hundred seventy-seven".