21700501 has 2 divisors, whose sum is σ = 21700502. Its totient is φ = 21700500.

The previous prime is 21700493. The next prime is 21700513. The reversal of 21700501 is 10500712.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20702500 + 998001 = 4550^2 + 999^2 .

It is a cyclic number.

It is not a de Polignac number, because 21700501 - 2³ = 21700493 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21700531) by changing a digit.

It is a nontrivial repunit in base 68.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10850250 + 10850251.

It is an arithmetic number, because the mean of its divisors is an integer number (10850251).

Almost surely, 2^21700501 is an apocalyptic number.

It is an amenable number.

21700501 is a deficient number, since it is larger than the sum of its proper divisors (1).

21700501 is an equidigital number, since it uses as much as digits as its factorization.

21700501 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 70, while the sum is 16.

The square root of 21700501 is about 4658.3796539140. The cubic root of 21700501 is about 278.9265917704.

It can be divided in two parts, 21700 and 501, that added together give a square (22201 = 149²).

The spelling of 21700501 in words is "twenty-one million, seven hundred thousand, five hundred one".