28077981 has 8 divisors (see below), whose sum is σ = 37615584. Its totient is φ = 18629520.

The previous prime is 28077979. The next prime is 28078019. The reversal of 28077981 is 18977082.

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

It is not a de Polignac number, because 28077981 - 2¹ = 28077979 is a prime.

It is a super-2 number, since 2×28077981² = 1576746034072722, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28077961) 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, 21546 + ... + 22811.

It is an arithmetic number, because the mean of its divisors is an integer number (4701948).

Almost surely, 2^28077981 is an apocalyptic number.

It is an amenable number.

28077981 is a deficient number, since it is larger than the sum of its proper divisors (9537603).

28077981 is a wasteful number, since it uses less digits than its factorization.

28077981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 44571.

The product of its (nonzero) digits is 56448, while the sum is 42.

The square root of 28077981 is about 5298.8660107612. The cubic root of 28077981 is about 303.9405361821.

The spelling of 28077981 in words is "twenty-eight million, seventy-seven thousand, nine hundred eighty-one".