28661631 has 8 divisors (see below), whose sum is σ = 38262144. Its totient is φ = 19084440.

The previous prime is 28661629. The next prime is 28661641. The reversal of 28661631 is 13616682.

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

It is not a de Polignac number, because 28661631 - 2¹ = 28661629 is a prime.

It is a super-2 number, since 2×28661631² = 1642978183160322, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 28661592 and 28661601.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28661641) 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, 2725 + ... + 8046.

It is an arithmetic number, because the mean of its divisors is an integer number (4782768).

Almost surely, 2^28661631 is an apocalyptic number.

28661631 is a deficient number, since it is larger than the sum of its proper divisors (9600513).

28661631 is a wasteful number, since it uses less digits than its factorization.

28661631 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11661.

The product of its digits is 10368, while the sum is 33.

The square root of 28661631 is about 5353.6558537134. The cubic root of 28661631 is about 306.0320889925.

It can be divided in two parts, 28661 and 631, that added together give a palindrome (29292).

The spelling of 28661631 in words is "twenty-eight million, six hundred sixty-one thousand, six hundred thirty-one".