1620533985 has 16 divisors (see below), whose sum is σ = 2963262336. Its totient is φ = 740815488.

The previous prime is 1620533969. The next prime is 1620534011. The reversal of 1620533985 is 5893350261.

It is not a de Polignac number, because 1620533985 - 2⁴ = 1620533969 is a prime.

It is a super-2 number, since 2×1620533985² = 5252260793079960450, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 7716724 + ... + 7716933.

It is an arithmetic number, because the mean of its divisors is an integer number (185203896).

Almost surely, 2^1620533985 is an apocalyptic number.

1620533985 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1620533985 is a deficient number, since it is larger than the sum of its proper divisors (1342728351).

1620533985 is a wasteful number, since it uses less digits than its factorization.

1620533985 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15433672.

The product of its (nonzero) digits is 194400, while the sum is 42.

The square root of 1620533985 is about 40255.8565304478. The cubic root of 1620533985 is about 1174.5893201871.

The spelling of 1620533985 in words is "one billion, six hundred twenty million, five hundred thirty-three thousand, nine hundred eighty-five".