21697071 has 16 divisors (see below), whose sum is σ = 31669248. Its totient is φ = 13104000.

The previous prime is 21697051. The next prime is 21697097. The reversal of 21697071 is 17079612.

It is not a de Polignac number, because 21697071 - 2⁶ = 21697007 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (33).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21697001) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 10146 + ... + 12096.

It is an arithmetic number, because the mean of its divisors is an integer number (1979328).

Almost surely, 2^21697071 is an apocalyptic number.

21697071 is a deficient number, since it is larger than the sum of its proper divisors (9972177).

21697071 is a wasteful number, since it uses less digits than its factorization.

21697071 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2302.

The product of its (nonzero) digits is 5292, while the sum is 33.

The square root of 21697071 is about 4658.0114856020. The cubic root of 21697071 is about 278.9118952031.

The spelling of 21697071 in words is "twenty-one million, six hundred ninety-seven thousand, seventy-one".