139781906 has 16 divisors (see below), whose sum is σ = 234055008. Its totient is φ = 62059200.

The previous prime is 139781903. The next prime is 139781909. The reversal of 139781906 is 609187931.

It is an interprime number because it is at equal distance from previous prime (139781903) and next prime (139781909).

It is not an unprimeable number, because it can be changed into a prime (139781903) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 72935 + ... + 74826.

It is an arithmetic number, because the mean of its divisors is an integer number (14628438).

Almost surely, 2^139781906 is an apocalyptic number.

139781906 is a deficient number, since it is larger than the sum of its proper divisors (94273102).

139781906 is a wasteful number, since it uses less digits than its factorization.

139781906 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 147817.

The product of its (nonzero) digits is 81648, while the sum is 44.

The square root of 139781906 is about 11822.9398205353. The cubic root of 139781906 is about 518.9796386689.

The spelling of 139781906 in words is "one hundred thirty-nine million, seven hundred eighty-one thousand, nine hundred six".