21672073 has 2 divisors, whose sum is σ = 21672074. Its totient is φ = 21672072.

The previous prime is 21672061. The next prime is 21672089. The reversal of 21672073 is 37027612.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18421264 + 3250809 = 4292^2 + 1803^2 .

It is a cyclic number.

It is not a de Polignac number, because 21672073 - 2⁵ = 21672041 is a prime.

It is not a weakly prime, because it can be changed into another prime (21672023) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10836036 + 10836037.

It is an arithmetic number, because the mean of its divisors is an integer number (10836037).

Almost surely, 2^21672073 is an apocalyptic number.

It is an amenable number.

21672073 is a deficient number, since it is larger than the sum of its proper divisors (1).

21672073 is an equidigital number, since it uses as much as digits as its factorization.

21672073 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3528, while the sum is 28.

The square root of 21672073 is about 4655.3273783913. The cubic root of 21672073 is about 278.8047391276.

Adding to 21672073 its reverse (37027612), we get a palindrome (58699685).

The spelling of 21672073 in words is "twenty-one million, six hundred seventy-two thousand, seventy-three".