21477793 has 2 divisors, whose sum is σ = 21477794. Its totient is φ = 21477792.

The previous prime is 21477763. The next prime is 21477803. The reversal of 21477793 is 39777412.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20493729 + 984064 = 4527^2 + 992^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21477793 is a prime.

It is a super-2 number, since 2×21477793² = 922591184301698, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21477763) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10738896 + 10738897.

It is an arithmetic number, because the mean of its divisors is an integer number (10738897).

Almost surely, 2^21477793 is an apocalyptic number.

It is an amenable number.

21477793 is a deficient number, since it is larger than the sum of its proper divisors (1).

21477793 is an equidigital number, since it uses as much as digits as its factorization.

21477793 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 74088, while the sum is 40.

The square root of 21477793 is about 4634.4139866870. The cubic root of 21477793 is about 277.9691191135.

The spelling of 21477793 in words is "twenty-one million, four hundred seventy-seven thousand, seven hundred ninety-three".