646738154 has 4 divisors (see below), whose sum is σ = 970107234. Its totient is φ = 323369076.

The previous prime is 646738129. The next prime is 646738177. The reversal of 646738154 is 451837646.

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

It can be written as a sum of positive squares in only one way, i.e., 639837025 + 6901129 = 25295^2 + 2627^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 161684537 + ... + 161684540.

Almost surely, 2^646738154 is an apocalyptic number.

646738154 is a deficient number, since it is larger than the sum of its proper divisors (323369080).

646738154 is a wasteful number, since it uses less digits than its factorization.

646738154 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 323369079.

The product of its digits is 483840, while the sum is 44.

The square root of 646738154 is about 25431.0470488338. The cubic root of 646738154 is about 864.7876806345.

It can be divided in two parts, 64673 and 8154, that added together give a palindrome (72827).

The spelling of 646738154 in words is "six hundred forty-six million, seven hundred thirty-eight thousand, one hundred fifty-four".