1640503551 has 4 divisors (see below), whose sum is σ = 2187338072. Its totient is φ = 1093669032.

The previous prime is 1640503547. The next prime is 1640503583. The reversal of 1640503551 is 1553050461.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 1640503551 - 2² = 1640503547 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1640503751) 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, 273417256 + ... + 273417261.

It is an arithmetic number, because the mean of its divisors is an integer number (546834518).

Almost surely, 2^1640503551 is an apocalyptic number.

1640503551 is a deficient number, since it is larger than the sum of its proper divisors (546834521).

1640503551 is an equidigital number, since it uses as much as digits as its factorization.

1640503551 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 546834520.

The product of its (nonzero) digits is 9000, while the sum is 30.

The square root of 1640503551 is about 40503.1301382992. The cubic root of 1640503551 is about 1179.3943916706.

The spelling of 1640503551 in words is "one billion, six hundred forty million, five hundred three thousand, five hundred fifty-one".