21612461 has 8 divisors (see below), whose sum is σ = 23314200. Its totient is φ = 19916352.

The previous prime is 21612431. The next prime is 21612497. The reversal of 21612461 is 16421612.

It can be written as a sum of positive squares in 4 ways, for example, as 175561 + 21436900 = 419^2 + 4630^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21612461 - 2⁶ = 21612397 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21612431) 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, 10115 + ... + 12063.

It is an arithmetic number, because the mean of its divisors is an integer number (2914275).

Almost surely, 2^21612461 is an apocalyptic number.

It is an amenable number.

21612461 is a deficient number, since it is larger than the sum of its proper divisors (1701739).

21612461 is a wasteful number, since it uses less digits than its factorization.

21612461 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2815.

The product of its digits is 576, while the sum is 23.

The square root of 21612461 is about 4648.9204123108. The cubic root of 21612461 is about 278.5488742016.

The spelling of 21612461 in words is "twenty-one million, six hundred twelve thousand, four hundred sixty-one".