1620400297 has 4 divisors (see below), whose sum is σ = 1630721476. Its totient is φ = 1610079120.

The previous prime is 1620400273. The next prime is 1620400321. The reversal of 1620400297 is 7920040261.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 7920040261 = 7 ⋅1131434323.

It is an interprime number because it is at equal distance from previous prime (1620400273) and next prime (1620400321).

It can be written as a sum of positive squares in 2 ways, for example, as 873143401 + 747256896 = 29549^2 + 27336^2 .

It is a cyclic number.

It is not a de Polignac number, because 1620400297 - 2²⁷ = 1486182569 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1620400097) 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, 5160354 + ... + 5160667.

It is an arithmetic number, because the mean of its divisors is an integer number (407680369).

Almost surely, 2^1620400297 is an apocalyptic number.

It is an amenable number.

1620400297 is a deficient number, since it is larger than the sum of its proper divisors (10321179).

1620400297 is a wasteful number, since it uses less digits than its factorization.

1620400297 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10321178.

The product of its (nonzero) digits is 6048, while the sum is 31.

The square root of 1620400297 is about 40254.1960173098. The cubic root of 1620400297 is about 1174.5570195552.

The spelling of 1620400297 in words is "one billion, six hundred twenty million, four hundred thousand, two hundred ninety-seven".