21747097 has 12 divisors (see below), whose sum is σ = 23632668. Its totient is φ = 19942400.

The previous prime is 21747073. The next prime is 21747101. The reversal of 21747097 is 79074712.

It can be written as a sum of positive squares in 6 ways, for example, as 10830681 + 10916416 = 3291^2 + 3304^2 .

It is a de Polignac number, because none of the positive numbers 2^k-21747097 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21747007) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 28197 + ... + 28957.

It is an arithmetic number, because the mean of its divisors is an integer number (1969389).

Almost surely, 2^21747097 is an apocalyptic number.

It is an amenable number.

21747097 is a deficient number, since it is larger than the sum of its proper divisors (1885571).

21747097 is an equidigital number, since it uses as much as digits as its factorization.

21747097 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 860 (or 819 counting only the distinct ones).

The product of its (nonzero) digits is 24696, while the sum is 37.

The square root of 21747097 is about 4663.3782818896. The cubic root of 21747097 is about 279.1260890405.

The spelling of 21747097 in words is "twenty-one million, seven hundred forty-seven thousand, ninety-seven".