21293777 has 2 divisors, whose sum is σ = 21293778. Its totient is φ = 21293776.

The previous prime is 21293761. The next prime is 21293803. The reversal of 21293777 is 77739212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 11282881 + 10010896 = 3359^2 + 3164^2 .

It is a cyclic number.

It is not a de Polignac number, because 21293777 - 2⁴ = 21293761 is a prime.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21293777.

It is not a weakly prime, because it can be changed into another prime (21293717) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10646888 + 10646889.

It is an arithmetic number, because the mean of its divisors is an integer number (10646889).

Almost surely, 2^21293777 is an apocalyptic number.

It is an amenable number.

21293777 is a deficient number, since it is larger than the sum of its proper divisors (1).

21293777 is an equidigital number, since it uses as much as digits as its factorization.

21293777 is an evil number, because the sum of its binary digits is even.

The product of its digits is 37044, while the sum is 38.

The square root of 21293777 is about 4614.5180680110. The cubic root of 21293777 is about 277.1729859977.

The spelling of 21293777 in words is "twenty-one million, two hundred ninety-three thousand, seven hundred seventy-seven".