21264377 has 4 divisors (see below), whose sum is σ = 21372516. Its totient is φ = 21156240.

The previous prime is 21264371. The next prime is 21264379. The reversal of 21264377 is 77346212.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 19571776 + 1692601 = 4424^2 + 1301^2 .

It is a cyclic number.

It is not a de Polignac number, because 21264377 - 2⁴ = 21264361 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21264371) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 53774 + ... + 54167.

It is an arithmetic number, because the mean of its divisors is an integer number (5343129).

Almost surely, 2^21264377 is an apocalyptic number.

It is an amenable number.

21264377 is a deficient number, since it is larger than the sum of its proper divisors (108139).

21264377 is a wasteful number, since it uses less digits than its factorization.

21264377 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 108138.

The product of its digits is 14112, while the sum is 32.

The square root of 21264377 is about 4611.3313695721. The cubic root of 21264377 is about 277.0453643767.

The spelling of 21264377 in words is "twenty-one million, two hundred sixty-four thousand, three hundred seventy-seven".