21396763 has 4 divisors (see below), whose sum is σ = 21759480. Its totient is φ = 21034048.

The previous prime is 21396743. The next prime is 21396769. The reversal of 21396763 is 36769312.

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

It is a cyclic number.

It is not a de Polignac number, because 21396763 - 2⁵ = 21396731 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21396769) 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, 181270 + ... + 181387.

It is an arithmetic number, because the mean of its divisors is an integer number (5439870).

Almost surely, 2^21396763 is an apocalyptic number.

21396763 is a deficient number, since it is larger than the sum of its proper divisors (362717).

21396763 is an equidigital number, since it uses as much as digits as its factorization.

21396763 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 362716.

The product of its digits is 40824, while the sum is 37.

The square root of 21396763 is about 4625.6635199720. The cubic root of 21396763 is about 277.6191107316.

The spelling of 21396763 in words is "twenty-one million, three hundred ninety-six thousand, seven hundred sixty-three".