1620657951 has 16 divisors (see below), whose sum is σ = 2373148800. Its totient is φ = 975621920.

The previous prime is 1620657949. The next prime is 1620657977. The reversal of 1620657951 is 1597560261.

It is a cyclic number.

It is not a de Polignac number, because 1620657951 - 2¹ = 1620657949 is a prime.

It is a Smith number, since the sum of its digits (42) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1620657911) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 159885 + ... + 169718.

It is an arithmetic number, because the mean of its divisors is an integer number (148321800).

Almost surely, 2^1620657951 is an apocalyptic number.

1620657951 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

1620657951 is a deficient number, since it is larger than the sum of its proper divisors (752490849).

1620657951 is a wasteful number, since it uses less digits than its factorization.

1620657951 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 329766.

The product of its (nonzero) digits is 113400, while the sum is 42.

The square root of 1620657951 is about 40257.3962272773. The cubic root of 1620657951 is about 1174.6192702794.

The spelling of 1620657951 in words is "one billion, six hundred twenty million, six hundred fifty-seven thousand, nine hundred fifty-one".