21901671 has 40 divisors (see below), whose sum is σ = 36520704. Its totient is φ = 12966480.

The previous prime is 21901639. The next prime is 21901703. The reversal of 21901671 is 17610912.

21901671 is an esthetic number in base 6, because in such base its adjacent digits differ by 1.

It is an interprime number because it is at equal distance from previous prime (21901639) and next prime (21901703).

It is not a de Polignac number, because 21901671 - 2⁵ = 21901639 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21901601) 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 39 ways as a sum of consecutive naturals, for example, 41616 + ... + 42138.

Almost surely, 2^21901671 is an apocalyptic number.

21901671 is a deficient number, since it is larger than the sum of its proper divisors (14619033).

21901671 is a wasteful number, since it uses less digits than its factorization.

21901671 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 593 (or 584 counting only the distinct ones).

The product of its (nonzero) digits is 756, while the sum is 27.

The square root of 21901671 is about 4679.9221147365. The cubic root of 21901671 is about 279.7858524154.

The spelling of 21901671 in words is "twenty-one million, nine hundred one thousand, six hundred seventy-one".