139435774921 has 9 divisors (see below), whose sum is σ = 141861563911. Its totient is φ = 137050798864.

The previous prime is 139435774903. The next prime is 139435774939. The reversal of 139435774921 is 129477534931.

The square root of 139435774921 is 373411.

It is a perfect power (a square), and thus also a powerful number.

It is an interprime number because it is at equal distance from previous prime (139435774903) and next prime (139435774939).

It can be written as a sum of positive squares in only one way, i.e., 106413616521 + 33022158400 = 326211^2 + 181720^2 .

It is a de Polignac number, because none of the positive numbers 2^k-139435774921 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (139435771921) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 22028085 + ... + 22034413.

Almost surely, 2^139435774921 is an apocalyptic number.

139435774921 is the 373411-st square number.

139435774921 is the 186706-th centered octagonal number.

It is an amenable number.

139435774921 is a deficient number, since it is larger than the sum of its proper divisors (2425788990).

139435774921 is an frugal number, since it uses more digits than its factorization.

139435774921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12776 (or 6388 counting only the distinct ones).

The product of its digits is 5715360, while the sum is 55.

The spelling of 139435774921 in words is "one hundred thirty-nine billion, four hundred thirty-five million, seven hundred seventy-four thousand, nine hundred twenty-one".