1620699381 has 64 divisors (see below), whose sum is σ = 2809128960. Its totient is φ = 904400640.

The previous prime is 1620699343. The next prime is 1620699401. The reversal of 1620699381 is 1839960261.

It is a happy number.

It is not a de Polignac number, because 1620699381 - 2¹⁰ = 1620698357 is a prime.

It is a super-2 number, since 2×1620699381² = 5253332967147566322, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1620699331) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 1658365 + ... + 1659341.

It is an arithmetic number, because the mean of its divisors is an integer number (43892640).

Almost surely, 2^1620699381 is an apocalyptic number.

It is an amenable number.

1620699381 is a deficient number, since it is larger than the sum of its proper divisors (1188429579).

1620699381 is a wasteful number, since it uses less digits than its factorization.

1620699381 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1191 (or 1185 counting only the distinct ones).

The product of its (nonzero) digits is 139968, while the sum is 45.

The square root of 1620699381 is about 40257.9107878191. The cubic root of 1620699381 is about 1174.6292793957.

The spelling of 1620699381 in words is "one billion, six hundred twenty million, six hundred ninety-nine thousand, three hundred eighty-one".