21787950 has 24 divisors (see below), whose sum is σ = 54034488. Its totient is φ = 5810080.

The previous prime is 21787949. The next prime is 21787979. The reversal of 21787950 is 5978712.

It is a junction number, because it is equal to n+sod(n) for n = 21787899 and 21787908.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 72477 + ... + 72776.

It is an arithmetic number, because the mean of its divisors is an integer number (2251437).

Almost surely, 2^21787950 is an apocalyptic number.

21787950 is an abundant number, since it is smaller than the sum of its proper divisors (32246538).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21787950 is a wasteful number, since it uses less digits than its factorization.

21787950 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 145268 (or 145263 counting only the distinct ones).

The product of its (nonzero) digits is 35280, while the sum is 39.

The square root of 21787950 is about 4667.7564203801. The cubic root of 21787950 is about 279.3007637738.

The spelling of 21787950 in words is "twenty-one million, seven hundred eighty-seven thousand, nine hundred fifty".