1642649391 has 12 divisors (see below), whose sum is σ = 2385827080. Its totient is φ = 1089048240.

The previous prime is 1642649387. The next prime is 1642649413. The reversal of 1642649391 is 1939462461.

It is not a de Polignac number, because 1642649391 - 2² = 1642649387 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 (1642649311) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 502561 + ... + 505818.

Almost surely, 2^1642649391 is an apocalyptic number.

1642649391 is a deficient number, since it is larger than the sum of its proper divisors (743177689).

1642649391 is a wasteful number, since it uses less digits than its factorization.

1642649391 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1008566 (or 1008563 counting only the distinct ones).

The product of its digits is 279936, while the sum is 45.

The square root of 1642649391 is about 40529.6112860708. The cubic root of 1642649391 is about 1179.9083982804.

The spelling of 1642649391 in words is "one billion, six hundred forty-two million, six hundred forty-nine thousand, three hundred ninety-one".