21764534 has 16 divisors (see below), whose sum is σ = 35729856. Its totient is φ = 9861000.

The previous prime is 21764513. The next prime is 21764537. The reversal of 21764534 is 43546712.

It is a self number, because there is not a number n which added to its sum of digits gives 21764534.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21764537) 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, 6209 + ... + 9059.

It is an arithmetic number, because the mean of its divisors is an integer number (2233116).

Almost surely, 2^21764534 is an apocalyptic number.

21764534 is a deficient number, since it is larger than the sum of its proper divisors (13965322).

21764534 is a wasteful number, since it uses less digits than its factorization.

21764534 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3211.

The product of its digits is 20160, while the sum is 32.

The square root of 21764534 is about 4665.2474746791. The cubic root of 21764534 is about 279.2006709699.

The spelling of 21764534 in words is "twenty-one million, seven hundred sixty-four thousand, five hundred thirty-four".