21851470 has 16 divisors (see below), whose sum is σ = 39500208. Its totient is φ = 8703360.

The previous prime is 21851461. The next prime is 21851503. The reversal of 21851470 is 7415812.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2124 + ... + 6943.

It is an arithmetic number, because the mean of its divisors is an integer number (2468763).

Almost surely, 2^21851470 is an apocalyptic number.

21851470 is a deficient number, since it is larger than the sum of its proper divisors (17648738).

21851470 is a wasteful number, since it uses less digits than its factorization.

21851470 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9315.

The product of its (nonzero) digits is 2240, while the sum is 28.

The square root of 21851470 is about 4674.5555938506. Note that the first 4 decimals coincide. The cubic root of 21851470 is about 279.5719223983.

It can be divided in two parts, 2185 and 1470, that added together give a triangular number (3655 = T₈₅).

The spelling of 21851470 in words is "twenty-one million, eight hundred fifty-one thousand, four hundred seventy".