16861621 has 8 divisors (see below), whose sum is σ = 19379520. Its totient is φ = 14371008.

The previous prime is 16861609. The next prime is 16861631. The reversal of 16861621 is 12616861.

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 16861621 - 2⁵ = 16861589 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 (16861601) 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, 5476 + ... + 7981.

It is an arithmetic number, because the mean of its divisors is an integer number (2422440).

Almost surely, 2^16861621 is an apocalyptic number.

It is an amenable number.

16861621 is a deficient number, since it is larger than the sum of its proper divisors (2517899).

16861621 is a wasteful number, since it uses less digits than its factorization.

16861621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13643.

The product of its digits is 3456, while the sum is 31.

The square root of 16861621 is about 4106.2904183703. The cubic root of 16861621 is about 256.4285880995.

The spelling of 16861621 in words is "sixteen million, eight hundred sixty-one thousand, six hundred twenty-one".