139657821 has 32 divisors (see below), whose sum is σ = 199065600. Its totient is φ = 86951040.

The previous prime is 139657811. The next prime is 139657867. The reversal of 139657821 is 128756931.

It is not a de Polignac number, because 139657821 - 2⁵ = 139657789 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (139657801) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 388840 + ... + 389198.

It is an arithmetic number, because the mean of its divisors is an integer number (6220800).

Almost surely, 2^139657821 is an apocalyptic number.

It is an amenable number.

139657821 is a deficient number, since it is larger than the sum of its proper divisors (59407779).

139657821 is a wasteful number, since it uses less digits than its factorization.

139657821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 529.

The product of its digits is 90720, while the sum is 42.

The square root of 139657821 is about 11817.6910181304. The cubic root of 139657821 is about 518.8260263857.

The spelling of 139657821 in words is "one hundred thirty-nine million, six hundred fifty-seven thousand, eight hundred twenty-one".