20151643 has 8 divisors (see below), whose sum is σ = 21365120. Its totient is φ = 18973440.

The previous prime is 20151619. The next prime is 20151667. The reversal of 20151643 is 34615102.

It is an interprime number because it is at equal distance from previous prime (20151619) and next prime (20151667).

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 20151643 - 2¹³ = 20143451 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20151683) 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, 7638 + ... + 9931.

It is an arithmetic number, because the mean of its divisors is an integer number (2670640).

Almost surely, 2^20151643 is an apocalyptic number.

20151643 is a deficient number, since it is larger than the sum of its proper divisors (1213477).

20151643 is a wasteful number, since it uses less digits than its factorization.

20151643 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17637.

The product of its (nonzero) digits is 720, while the sum is 22.

The square root of 20151643 is about 4489.0581417487. The cubic root of 20151643 is about 272.1260724313.

Adding to 20151643 its reverse (34615102), we get a palindrome (54766745).

The spelling of 20151643 in words is "twenty million, one hundred fifty-one thousand, six hundred forty-three".