1620899279 has 4 divisors (see below), whose sum is σ = 1625131776. Its totient is φ = 1616666784.

The previous prime is 1620899261. The next prime is 1620899303. The reversal of 1620899279 is 9729980261.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 9729980261 = 31 ⋅313870331.

It is a cyclic number.

It is not a de Polignac number, because 1620899279 - 2¹² = 1620895183 is a prime.

It is a super-3 number, since 3×1620899279³ (a number of 29 digits) contains 333 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1620899279.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1620899209) 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, 2115674 + ... + 2116439.

It is an arithmetic number, because the mean of its divisors is an integer number (406282944).

Almost surely, 2^1620899279 is an apocalyptic number.

1620899279 is a deficient number, since it is larger than the sum of its proper divisors (4232497).

1620899279 is an equidigital number, since it uses as much as digits as its factorization.

1620899279 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4232496.

The product of its (nonzero) digits is 979776, while the sum is 53.

The square root of 1620899279 is about 40260.3934282813. The cubic root of 1620899279 is about 1174.6775705621.

The spelling of 1620899279 in words is "one billion, six hundred twenty million, eight hundred ninety-nine thousand, two hundred seventy-nine".