1621224861 has 8 divisors (see below), whose sum is σ = 2175402144. Its totient is φ = 1073932080.

The previous prime is 1621224859. The next prime is 1621224889. The reversal of 1621224861 is 1684221261.

It is a happy number.

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

It is not a de Polignac number, because 1621224861 - 2¹ = 1621224859 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1621224821) 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, 1720575 + ... + 1721516.

It is an arithmetic number, because the mean of its divisors is an integer number (271925268).

Almost surely, 2^1621224861 is an apocalyptic number.

It is an amenable number.

1621224861 is a deficient number, since it is larger than the sum of its proper divisors (554177283).

1621224861 is a wasteful number, since it uses less digits than its factorization.

1621224861 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3442251.

The product of its digits is 9216, while the sum is 33.

The square root of 1621224861 is about 40264.4366780413. The cubic root of 1621224861 is about 1174.7562158494.

The spelling of 1621224861 in words is "one billion, six hundred twenty-one million, two hundred twenty-four thousand, eight hundred sixty-one".