21987035 has 24 divisors (see below), whose sum is σ = 32503680. Its totient is φ = 14187264.

The previous prime is 21987019. The next prime is 21987041. The reversal of 21987035 is 53078912.

It is not a de Polignac number, because 21987035 - 2⁴ = 21987019 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (35).

It is a junction number, because it is equal to n+sod(n) for n = 21986986 and 21987004.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1526 + ... + 6804.

It is an arithmetic number, because the mean of its divisors is an integer number (1354320).

Almost surely, 2^21987035 is an apocalyptic number.

21987035 is a deficient number, since it is larger than the sum of its proper divisors (10516645).

21987035 is a wasteful number, since it uses less digits than its factorization.

21987035 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5315 (or 5308 counting only the distinct ones).

The product of its (nonzero) digits is 15120, while the sum is 35.

The square root of 21987035 is about 4689.0334824994. The cubic root of 21987035 is about 280.1488791586.

The spelling of 21987035 in words is "twenty-one million, nine hundred eighty-seven thousand, thirty-five".