21231777037 has 4 divisors (see below), whose sum is σ = 22480705116. Its totient is φ = 19982848960.

The previous prime is 21231777029. The next prime is 21231777067. The reversal of 21231777037 is 73077713212.

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

It can be written as a sum of positive squares in 2 ways, for example, as 12219312681 + 9012464356 = 110541^2 + 94934^2 .

It is a cyclic number.

It is not a de Polignac number, because 21231777037 - 2³ = 21231777029 is a prime.

It is a super-2 number, since 2×21231777037² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21231777067) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 624464014 + ... + 624464047.

It is an arithmetic number, because the mean of its divisors is an integer number (5620176279).

Almost surely, 2^21231777037 is an apocalyptic number.

It is an amenable number.

21231777037 is a deficient number, since it is larger than the sum of its proper divisors (1248928079).

21231777037 is a wasteful number, since it uses less digits than its factorization.

21231777037 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1248928078.

The product of its (nonzero) digits is 86436, while the sum is 40.

The spelling of 21231777037 in words is "twenty-one billion, two hundred thirty-one million, seven hundred seventy-seven thousand, thirty-seven".