21023672 has 8 divisors (see below), whose sum is σ = 39419400. Its totient is φ = 10511832.

The previous prime is 21023663. The next prime is 21023677. The reversal of 21023672 is 27632012.

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

It is a super-4 number, since 4×21023672⁴ (a number of 30 digits) contains 4444 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21023677) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1313972 + ... + 1313987.

It is an arithmetic number, because the mean of its divisors is an integer number (4927425).

Almost surely, 2^21023672 is an apocalyptic number.

It is an amenable number.

21023672 is a deficient number, since it is larger than the sum of its proper divisors (18395728).

21023672 is a wasteful number, since it uses less digits than its factorization.

21023672 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2627965 (or 2627961 counting only the distinct ones).

The product of its (nonzero) digits is 1008, while the sum is 23.

The square root of 21023672 is about 4585.1577944494. The cubic root of 21023672 is about 275.9960441917.

Adding to 21023672 its reverse (27632012), we get a palindrome (48655684).

The spelling of 21023672 in words is "twenty-one million, twenty-three thousand, six hundred seventy-two".