139772821 has 8 divisors (see below), whose sum is σ = 141067584. Its totient is φ = 138483840.

The previous prime is 139772803. The next prime is 139772839. The reversal of 139772821 is 128277931.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (139772803) and next prime (139772839).

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 139772821 - 2⁹ = 139772309 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 (139772891) 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, 57766 + ... + 60136.

It is an arithmetic number, because the mean of its divisors is an integer number (17633448).

Almost surely, 2^139772821 is an apocalyptic number.

It is an amenable number.

139772821 is a deficient number, since it is larger than the sum of its proper divisors (1294763).

139772821 is a wasteful number, since it uses less digits than its factorization.

139772821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2891.

The product of its digits is 42336, while the sum is 40.

The square root of 139772821 is about 11822.5556035910. Note that the first 3 decimals coincide. The cubic root of 139772821 is about 518.9683948861.

The spelling of 139772821 in words is "one hundred thirty-nine million, seven hundred seventy-two thousand, eight hundred twenty-one".