21979948 has 24 divisors (see below), whose sum is σ = 39463200. Its totient is φ = 10707840.

The previous prime is 21979943. The next prime is 21979949. The reversal of 21979948 is 84997912.

It is a super-2 number, since 2×21979948² = 966236228165408, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21979943) 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, 41928 + ... + 42448.

It is an arithmetic number, because the mean of its divisors is an integer number (1644300).

Almost surely, 2^21979948 is an apocalyptic number.

It is an amenable number.

21979948 is a deficient number, since it is larger than the sum of its proper divisors (17483252).

21979948 is a wasteful number, since it uses less digits than its factorization.

21979948 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 777 (or 775 counting only the distinct ones).

The product of its digits is 326592, while the sum is 49.

The square root of 21979948 is about 4688.2777221491. The cubic root of 21979948 is about 280.1187761386.

The spelling of 21979948 in words is "twenty-one million, nine hundred seventy-nine thousand, nine hundred forty-eight".