21010749 has 8 divisors (see below), whose sum is σ = 28045632. Its totient is φ = 13991520.

The previous prime is 21010741. The next prime is 21010757. The reversal of 21010749 is 94701012.

It is an interprime number because it is at equal distance from previous prime (21010741) and next prime (21010757).

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21010749 - 2³ = 21010741 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21010741) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 304 + ... + 6489.

It is an arithmetic number, because the mean of its divisors is an integer number (3505704).

Almost surely, 2^21010749 is an apocalyptic number.

It is an amenable number.

21010749 is a deficient number, since it is larger than the sum of its proper divisors (7034883).

21010749 is a wasteful number, since it uses less digits than its factorization.

21010749 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7827.

The product of its (nonzero) digits is 504, while the sum is 24.

The square root of 21010749 is about 4583.7483569673. The cubic root of 21010749 is about 275.9394821105.

The spelling of 21010749 in words is "twenty-one million, ten thousand, seven hundred forty-nine".