21700497 has 32 divisors (see below), whose sum is σ = 36852480. Its totient is φ = 11047680.

The previous prime is 21700493. The next prime is 21700501. The reversal of 21700497 is 79400712.

It is an interprime number because it is at equal distance from previous prime (21700493) and next prime (21700501).

It is not a de Polignac number, because 21700497 - 2² = 21700493 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21700493) 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 in 31 ways as a sum of consecutive naturals, for example, 6547 + ... + 9287.

It is an arithmetic number, because the mean of its divisors is an integer number (1151640).

Almost surely, 2^21700497 is an apocalyptic number.

It is an amenable number.

21700497 is a deficient number, since it is larger than the sum of its proper divisors (15151983).

21700497 is a wasteful number, since it uses less digits than its factorization.

21700497 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2793.

The product of its (nonzero) digits is 3528, while the sum is 30.

The square root of 21700497 is about 4658.3792245802. The cubic root of 21700497 is about 278.9265746324.

The spelling of 21700497 in words is "twenty-one million, seven hundred thousand, four hundred ninety-seven".