21961672 has 8 divisors (see below), whose sum is σ = 41178150. Its totient is φ = 10980832.

The previous prime is 21961627. The next prime is 21961697. The reversal of 21961672 is 27616912.

It can be written as a sum of positive squares in only one way, i.e., 18096516 + 3865156 = 4254^2 + 1966^2 .

It is a tau number, because it is divible by the number of its divisors (8).

It is a super-3 number, since 3×21961672³ (a number of 23 digits) contains 333 as substring.

It is an unprimeable number.

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 as a sum of consecutive naturals, namely, 1372597 + ... + 1372612.

Almost surely, 2^21961672 is an apocalyptic number.

It is an amenable number.

21961672 is a deficient number, since it is larger than the sum of its proper divisors (19216478).

21961672 is a wasteful number, since it uses less digits than its factorization.

21961672 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2745215 (or 2745211 counting only the distinct ones).

The product of its digits is 9072, while the sum is 34.

The square root of 21961672 is about 4686.3282002011. The cubic root of 21961672 is about 280.0411164110.

The spelling of 21961672 in words is "twenty-one million, nine hundred sixty-one thousand, six hundred seventy-two".