1620611431 has 4 divisors (see below), whose sum is σ = 1621424952. Its totient is φ = 1619797912.

The previous prime is 1620611383. The next prime is 1620611449. The reversal of 1620611431 is 1341160261.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1341160261 = 7 ⋅191594323.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1620611431 is a prime.

It is a super-2 number, since 2×1620611431² = 5252762820575735522, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1620611396 and 1620611405.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1620611131) 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 3 ways as a sum of consecutive naturals, for example, 403765 + ... + 407758.

It is an arithmetic number, because the mean of its divisors is an integer number (405356238).

Almost surely, 2^1620611431 is an apocalyptic number.

1620611431 is a deficient number, since it is larger than the sum of its proper divisors (813521).

1620611431 is an equidigital number, since it uses as much as digits as its factorization.

1620611431 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 813520.

The product of its (nonzero) digits is 864, while the sum is 25.

The square root of 1620611431 is about 40256.8184411039. The cubic root of 1620611431 is about 1174.6080312614.

Adding to 1620611431 its reverse (1341160261), we get a palindrome (2961771692).

The spelling of 1620611431 in words is "one billion, six hundred twenty million, six hundred eleven thousand, four hundred thirty-one".