21158701 has 2 divisors, whose sum is σ = 21158702. Its totient is φ = 21158700.

The previous prime is 21158677. The next prime is 21158729. The reversal of 21158701 is 10785112.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 21068100 + 90601 = 4590^2 + 301^2 .

It is a cyclic number.

It is not a de Polignac number, because 21158701 - 2¹⁵ = 21125933 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21158201) 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 as a sum of consecutive naturals, namely, 10579350 + 10579351.

It is an arithmetic number, because the mean of its divisors is an integer number (10579351).

Almost surely, 2^21158701 is an apocalyptic number.

It is an amenable number.

21158701 is a deficient number, since it is larger than the sum of its proper divisors (1).

21158701 is an equidigital number, since it uses as much as digits as its factorization.

21158701 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 560, while the sum is 25.

The square root of 21158701 is about 4599.8588021808. The cubic root of 21158701 is about 276.5856647434.

It can be divided in two parts, 2115 and 8701, that added together give a square (10816 = 104²).

The spelling of 21158701 in words is "twenty-one million, one hundred fifty-eight thousand, seven hundred one".