21461004 has 48 divisors (see below), whose sum is σ = 58917600. Its totient is φ = 6732288.

The previous prime is 21460993. The next prime is 21461023. The reversal of 21461004 is 40016412.

Added to its reverse (40016412) it gives a triangular number (61477416 = T₁₁₀₈₈).

It is a Harshad number since it is a multiple of its sum of digits (18).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4009 + ... + 7680.

It is an arithmetic number, because the mean of its divisors is an integer number (1227450).

Almost surely, 2^21461004 is an apocalyptic number.

It is an amenable number.

21461004 is an abundant number, since it is smaller than the sum of its proper divisors (37456596).

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

21461004 is a wasteful number, since it uses less digits than its factorization.

21461004 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11719 (or 11711 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 18.

The square root of 21461004 is about 4632.6022924486. The cubic root of 21461004 is about 277.8966715693.

Adding to 21461004 its reverse (40016412), we get a palindrome (61477416).

The spelling of 21461004 in words is "twenty-one million, four hundred sixty-one thousand, four".