21319745 has 8 divisors (see below), whose sum is σ = 25717416. Its totient is φ = 16966656.

The previous prime is 21319741. The next prime is 21319747. The reversal of 21319745 is 54791312.

It can be written as a sum of positive squares in 4 ways, for example, as 3713329 + 17606416 = 1927^2 + 4196^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21319745 - 2² = 21319741 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21319741) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 10082 + ... + 12011.

It is an arithmetic number, because the mean of its divisors is an integer number (3214677).

Almost surely, 2^21319745 is an apocalyptic number.

It is an amenable number.

21319745 is a deficient number, since it is larger than the sum of its proper divisors (4397671).

21319745 is a wasteful number, since it uses less digits than its factorization.

21319745 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22291.

The product of its digits is 7560, while the sum is 32.

The square root of 21319745 is about 4617.3309389733. The cubic root of 21319745 is about 277.2856120827.

The spelling of 21319745 in words is "twenty-one million, three hundred nineteen thousand, seven hundred forty-five".