21607861 has 8 divisors (see below), whose sum is σ = 24147648. Its totient is φ = 19164000.

The previous prime is 21607853. The next prime is 21607891. The reversal of 21607861 is 16870612.

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

It is a cyclic number.

It is not a de Polignac number, because 21607861 - 2³ = 21607853 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21607811) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 23505 + ... + 24406.

It is an arithmetic number, because the mean of its divisors is an integer number (3018456).

Almost surely, 2^21607861 is an apocalyptic number.

It is an amenable number.

21607861 is a deficient number, since it is larger than the sum of its proper divisors (2539787).

21607861 is a wasteful number, since it uses less digits than its factorization.

21607861 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 47963.

The product of its (nonzero) digits is 4032, while the sum is 31.

The square root of 21607861 is about 4648.4256474639. The cubic root of 21607861 is about 278.5291106689.

The spelling of 21607861 in words is "twenty-one million, six hundred seven thousand, eight hundred sixty-one".