1621220143 has 4 divisors (see below), whose sum is σ = 1625263488. Its totient is φ = 1617176800.

The previous prime is 1621220137. The next prime is 1621220149. The reversal of 1621220143 is 3410221261.

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

It is an interprime number because it is at equal distance from previous prime (1621220137) and next prime (1621220149).

It is a cyclic number.

It is not a de Polignac number, because 1621220143 - 2²⁵ = 1587665711 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1621220149) 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, 2021071 + ... + 2021872.

It is an arithmetic number, because the mean of its divisors is an integer number (406315872).

Almost surely, 2^1621220143 is an apocalyptic number.

1621220143 is a deficient number, since it is larger than the sum of its proper divisors (4043345).

1621220143 is an equidigital number, since it uses as much as digits as its factorization.

1621220143 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4043344.

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

The square root of 1621220143 is about 40264.3780903170. The cubic root of 1621220143 is about 1174.7550762778.

The spelling of 1621220143 in words is "one billion, six hundred twenty-one million, two hundred twenty thousand, one hundred forty-three".