21461500 has 24 divisors (see below), whose sum is σ = 46873008. Its totient is φ = 8584400.

The previous prime is 21461467. The next prime is 21461521. The reversal of 21461500 is 516412.

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, 20962 + ... + 21961.

It is an arithmetic number, because the mean of its divisors is an integer number (1953042).

Almost surely, 2^21461500 is an apocalyptic number.

21461500 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21461500 is an abundant number, since it is smaller than the sum of its proper divisors (25411508).

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

21461500 is a wasteful number, since it uses less digits than its factorization.

21461500 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 42942 (or 42930 counting only the distinct ones).

The product of its (nonzero) digits is 240, while the sum is 19.

The square root of 21461500 is about 4632.6558257656. The cubic root of 21461500 is about 277.8988124397.

Adding to 21461500 its reverse (516412), we get a palindrome (21977912).

The spelling of 21461500 in words is "twenty-one million, four hundred sixty-one thousand, five hundred".