21523763 has 2 divisors, whose sum is σ = 21523764. Its totient is φ = 21523762.

The previous prime is 21523753. The next prime is 21523769. The reversal of 21523763 is 36732512.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21523763 - 2¹⁴ = 21507379 is a prime.

It is not a weakly prime, because it can be changed into another prime (21523769) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10761881 + 10761882.

It is an arithmetic number, because the mean of its divisors is an integer number (10761882).

Almost surely, 2^21523763 is an apocalyptic number.

21523763 is a deficient number, since it is larger than the sum of its proper divisors (1).

21523763 is an equidigital number, since it uses as much as digits as its factorization.

21523763 is an evil number, because the sum of its binary digits is even.

The product of its digits is 7560, while the sum is 29.

The square root of 21523763 is about 4639.3709702933. The cubic root of 21523763 is about 278.1672948850.

The spelling of 21523763 in words is "twenty-one million, five hundred twenty-three thousand, seven hundred sixty-three".