21621460 has 24 divisors (see below), whose sum is σ = 51891840. Its totient is φ = 7413024.

The previous prime is 21621437. The next prime is 21621463. The reversal of 21621460 is 6412612.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21621463) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 77080 + ... + 77359.

It is an arithmetic number, because the mean of its divisors is an integer number (2162160).

Almost surely, 2^21621460 is an apocalyptic number.

21621460 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21621460 is an abundant number, since it is smaller than the sum of its proper divisors (30270380).

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

21621460 is a wasteful number, since it uses less digits than its factorization.

21621460 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 154455 (or 154453 counting only the distinct ones).

The product of its (nonzero) digits is 576, while the sum is 22.

The square root of 21621460 is about 4649.8881706983. Note that the first 3 decimals coincide. The cubic root of 21621460 is about 278.5875295787.

The spelling of 21621460 in words is "twenty-one million, six hundred twenty-one thousand, four hundred sixty".