21860761 has 4 divisors (see below), whose sum is σ = 23542372. Its totient is φ = 20179152.

The previous prime is 21860731. The next prime is 21860771. The reversal of 21860761 is 16706812.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 4596736 + 17264025 = 2144^2 + 4155^2 .

It is a cyclic number.

It is not a de Polignac number, because 21860761 - 2¹⁹ = 21336473 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21860701) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 840786 + ... + 840811.

It is an arithmetic number, because the mean of its divisors is an integer number (5885593).

Almost surely, 2^21860761 is an apocalyptic number.

It is an amenable number.

21860761 is a deficient number, since it is larger than the sum of its proper divisors (1681611).

21860761 is a wasteful number, since it uses less digits than its factorization.

21860761 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1681610.

The product of its (nonzero) digits is 4032, while the sum is 31.

The square root of 21860761 is about 4675.5492725454. The cubic root of 21860761 is about 279.6115403992.

The spelling of 21860761 in words is "twenty-one million, eight hundred sixty thousand, seven hundred sixty-one".